### Retrieve spectral data using SparclClient

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Examples of initializing the client and retrieving spectral data for specific IDs.

```python
specids = [394069118933821440, 1355741587413428224, 1355617892355303424,
  1355615143576233984, 1355661872820414464, 1355755331308775424,
  1355716848401803264]
client = client.SparclClient(url='http://localhost:8030/sparc')
client.retrieve(specids)[0].keys() # >> dict_keys(['flux','loglam'])

data0 = client.retrieve(specids,columns='flux')
f'{len(str(data0)):,}'   # -> '3,435,687'

dataall = client.retrieve(specids,columns=allc)
f'{len(str(dataall)):,}' # -> '27,470,052'
```

--------------------------------

### Check SPARCL version via HTTPie

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Example command to check the server version using HTTPie.

```bash
http :8030/sparc/version
```

--------------------------------

### Get Available Fields

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Retrieves a list of all fields available from data sets in the SPARCL database.

```python
>>> client = SparclClient(announcement=False)
>>> sorted(client.get_available_fields())
['data_release', 'datasetgroup', 'dateobs', 'dateobs_center', 'dec', 'exptime', 'extra_files', 'file', 'flux', 'instrument', 'ivar', 'mask', 'model', 'ra', 'redshift', 'redshift_err', 'redshift_warning', 'site', 'sparcl_id', 'specid', 'specprimary', 'spectype', 'survey', 'targetid', 'telescope', 'updated', 'wave_sigma', 'wavelength', 'wavemax', 'wavemin']
```

--------------------------------

### Get Default Fields

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Retrieves fields tagged as 'default' that are used for the default include parameter in retrieval operations.

```python
>>> client = SparclClient(announcement=False)
>>> client.get_default_fields()
['dec', 'flux', 'ra', 'sparcl_id', 'specid', 'wavelength']
```

--------------------------------

### Importing specutils and dependencies

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/specutils.html

Initializes the module by importing necessary libraries, including handling version differences for the Spectrum class.

```python
"""Functions for converting SPARCL results to specutils objects.
"""
import numpy as np
try:
    # specutils >= 2.0
    from specutils import Spectrum
except ImportError:
    from specutils import Spectrum1D as Spectrum
from specutils import SpectrumCollection, SpectrumList
from astropy.nddata import InverseVariance
import astropy.units as u
```

--------------------------------

### get_default_fields(dataset_list=None)

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Get fields tagged as 'default' that are in DATASET_LIST.

```APIDOC
## get_default_fields(dataset_list=None)

### Description
Get fields tagged as 'default' that are in DATASET_LIST. These are the fields used for the DEFAULT value of the include parameter of client.retrieve().

### Parameters
- **dataset_list** (list) - Optional - List of data sets from which to get the default fields. Defaults to None.

### Returns
- **list** - List of fields tagged as 'default'.
```

--------------------------------

### Run tests against PAT server

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Commands to set the server URL and execute tests against the PAT server.

```bash
export serverurl=https://sparc1.datalab.noirlab.edu/
python -m unittest tests.tests_api
```

--------------------------------

### Initialize Counter Objects

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Demonstrates various ways to instantiate a Counter object using iterables, mappings, or keyword arguments.

```python
>>> c = Counter()                           # a new, empty counter
>>> c = Counter('gallahad')                 # a new counter from an iterable
>>> c = Counter({'a': 4, 'b': 2})           # a new counter from a mapping
>>> c = Counter(a=4, b=2)                   # a new counter from keyword args
```

--------------------------------

### Retrieve spectra by SPARCL ID

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Demonstrates how to initialize the client and retrieve records using a list of SPARCL IDs.

```python
>>> client = SparclClient(announcement=False)
>>> ids = client.find(limit=1).ids
>>> inc = ['sparcl_id', 'flux', 'wavelength', 'model']
>>> ret = client.retrieve(uuid_list=ids, include=inc)
>>> type(ret.records[0].wavelength)
<class 'numpy.ndarray'>
```

--------------------------------

### Initialize SparclClient

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Instantiate the client with announcements disabled.

```python
>>> client = SparclClient(announcement=False)
```

--------------------------------

### Define namedtuple factory function

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

The implementation of namedtuple, which creates a subclass of tuple with named fields. Includes examples of usage in the docstring.

```python
def namedtuple(typename, field_names, *, rename=False, defaults=None, module=None):
    """Returns a new subclass of tuple with named fields.

    >>> Point = namedtuple('Point', ['x', 'y'])
    >>> Point.__doc__                   # docstring for the new class
    'Point(x, y)'
    >>> p = Point(11, y=22)             # instantiate with positional args or keywords
    >>> p[0] + p[1]                     # indexable like a plain tuple
    33
    >>> x, y = p                        # unpack like a regular tuple
    >>> x, y
    (11, 22)
    >>> p.x + p.y                       # fields also accessible by name
    33
    >>> d = p._asdict()                 # convert to a dictionary
    >>> d['x']
    11
    >>> Point(**d)                      # convert from a dictionary
    Point(x=11, y=22)
    >>> p._replace(x=100)               # _replace() is like str.replace() but targets named fields
    Point(x=100, y=22)

    """

    # Validate the field names.  At the user's option, either generate an error
    # message or automatically replace the field name with a valid name.
    if isinstance(field_names, str):
        field_names = field_names.replace(',', ' ').split()
    field_names = list(map(str, field_names))
    typename = _sys.intern(str(typename))

    if rename:
        seen = set()
        for index, name in enumerate(field_names):
            if (not name.isidentifier()
                or _iskeyword(name)
                or name.startswith('_')
                or name in seen):
                field_names[index] = f'_{index}'
            seen.add(name)

    for name in [typename] + field_names:
        if type(name) is not str:
            raise TypeError('Type names and field names must be strings')
        if not name.isidentifier():
            raise ValueError('Type names and field names must be valid '
                             f'identifiers: {name!r}')
        if _iskeyword(name):
            raise ValueError('Type names and field names cannot be a '
                             f'keyword: {name!r}')

    seen = set()
    for name in field_names:
        if name.startswith('_') and not rename:
            raise ValueError('Field names cannot start with an underscore: '
                             f'{name!r}')
        if name in seen:
            raise ValueError(f'Encountered duplicate field name: {name!r}')
        seen.add(name)

    field_defaults = {}
    if defaults is not None:
        defaults = tuple(defaults)
        if len(defaults) > len(field_names):
            raise TypeError('Got more default values than field names')
        field_defaults = dict(reversed(list(zip(reversed(field_names),
                                                reversed(defaults)))))

    # Variables used in the methods and docstrings
    field_names = tuple(map(_sys.intern, field_names))
    num_fields = len(field_names)
    arg_list = ', '.join(field_names)
    if num_fields == 1:
        arg_list += ','
    repr_fmt = '(' + ', '.join(f'{name}=%r' for name in field_names) + ')'
    tuple_new = tuple.__new__
    _dict, _tuple, _len, _map, _zip = dict, tuple, len, map, zip

    # Create all the named tuple methods to be added to the class namespace

    namespace = {
        '_tuple_new': tuple_new,
        '__builtins__': {},
        '__name__': f'namedtuple_{typename}',
    }
    code = f'lambda _cls, {arg_list}: _tuple_new(_cls, ({arg_list}))'
    __new__ = eval(code, namespace)
    __new__.__name__ = '__new__'
    __new__.__doc__ = f'Create new instance of {typename}({arg_list})'
    if defaults is not None:
        __new__.__defaults__ = defaults

    @classmethod
    def _make(cls, iterable):
        result = tuple_new(cls, iterable)
        if _len(result) != num_fields:
            raise TypeError(f'Expected {num_fields} arguments, got {len(result)}')
        return result
```

--------------------------------

### Run tests against DEV server

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Command to execute tests against a local development server.

```bash
serverurl=http://localhost:8050 python -m unittest tests.tests_api
```

--------------------------------

### Retrieve spectra by specid

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Demonstrates how to retrieve specific spectra records using a list of specids.

```python
>>> client = SparclClient(announcement=False)
>>> sids = [4753625089450465280, 1254253099313293312]
>>> inc = ['specid', 'flux', 'wavelength', 'model']
>>> ret = client.retrieve_by_specid(specid_list=sids, include=inc)
>>> len(ret.records[0].wavelength)
4617
```

--------------------------------

### Initialize Retrieved class

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/Results.html

Constructor for the Retrieved class which holds spectral records.

```python
def __init__(self, dict_list, client=None):
    super().__init__(dict_list, client=client)
```

--------------------------------

### SparclClient Constructor

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Initializes a new instance of the SparclClient to interface with the SPARCL Server.

```APIDOC
## SparclClient(url='https://astrosparcl.datalab.noirlab.edu', verbose=False, connect_timeout=1.1, read_timeout=5400, announcement=True)

### Description
Initializes the client connection to the SPARCL server. Throws an exception if the client version is incompatible with the server.

### Parameters
- **url** (str) - Optional - Base URL of SPARCL Server.
- **verbose** (bool) - Optional - Set to True for detailed output.
- **connect_timeout** (float) - Optional - Seconds to wait for connection.
- **read_timeout** (float) - Optional - Seconds to wait for server response.
- **announcement** (bool) - Optional - Enable or disable SPARCL announcements.
```

--------------------------------

### Check API version

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Demonstrates how to retrieve the version of the Server REST API currently in use.

```python
>>> client = SparclClient(announcement=False)
>>> client.version
13.0
```

--------------------------------

### version

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Returns the version of the Server REST API used by the client.

```APIDOC
## version

### Description
Returns the version of the Server REST API currently in use. If the version is not cached, it fetches it from the server.

### Returns
- **float** - The API version number.
```

--------------------------------

### to_SpectrumList(results, *, flux_unit=None, wave_unit=None)

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/specutils.html

Converts retrieved SPARCL results into a specutils.SpectrumList object.

```APIDOC
## to_SpectrumList

### Description
Converts a `sparcl.Results.Retrieved` object into a `specutils.SpectrumList` object. If units are not provided, they are automatically resolved.

### Parameters
- **results** (sparcl.Results.Retrieved) - Required - The retrieved results to convert.
- **flux_unit** (str) - Optional - Unit string for flux. If None, resolved via _get_units().
- **wave_unit** (str) - Optional - Unit string for wavelength. If None, resolved via _get_units().

### Returns
- **SpectrumList** (specutils.SpectrumList) - The converted spectrum list object.
```

--------------------------------

### Run doctests

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Standard boilerplate for executing doctests when the module is run as a script.

```python
if __name__ == "__main__":
    import doctest

    doctest.testmod()
```

--------------------------------

### login(email, password=None)

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Login to the SPARCL service.

```APIDOC
## login(email, password=None)

### Description
Login to the SPARCL service.

### Parameters
- **email** (str) - Required - User login email.
- **password** (str) - Optional - User SSO password. If not given, the output will prompt the user to enter in their SSO password.

### Returns
- **None**
```

--------------------------------

### OrderedDict Metadata and Views

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Methods for calculating memory usage and providing dictionary views.

```python
def __sizeof__(self):
    sizeof = _sys.getsizeof
    n = len(self) + 1                       # number of links including root
    size = sizeof(self.__dict__)            # instance dictionary
    size += sizeof(self.__map) * 2          # internal dict and inherited dict
    size += sizeof(self.__hardroot) * n     # link objects
    size += sizeof(self.__root) * n         # proxy objects
    return size
```

```python
def keys(self):
    "D.keys() -> a set-like object providing a view on D's keys"
    return _OrderedDictKeysView(self)
```

```python
def items(self):
    "D.items() -> a set-like object providing a view on D's items"
    return _OrderedDictItemsView(self)
```

```python
def values(self):
    "D.values() -> an object providing a view on D's values"
    return _OrderedDictValuesView(self)
```

--------------------------------

### OrderedDict Serialization and Creation

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Methods for pickling, copying, and creating instances from iterables.

```python
def __reduce__(self):
    'Return state information for pickling'
    inst_dict = vars(self).copy()
    for k in vars(OrderedDict()):
        inst_dict.pop(k, None)
    return self.__class__, (), inst_dict or None, None, iter(self.items())
```

```python
def copy(self):
    'od.copy() -> a shallow copy of od'
    return self.__class__(self)
```

```python
@classmethod
def fromkeys(cls, iterable, value=None):
    '''Create a new ordered dictionary with keys from iterable and values set to value.
    '''
    self = cls()
    for key in iterable:
        self[key] = value
    return self
```

--------------------------------

### OrderedDict Utility Methods

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Methods for popping keys, setting defaults, and representation.

```python
def pop(self, key, default=__marker):
    '''od.pop(k[,d]) -> v, remove specified key and return the corresponding
    value.  If key is not found, d is returned if given, otherwise KeyError
    is raised.

    '''
    if key in self:
        result = self[key]
        del self[key]
        return result
    if default is self.__marker:
        raise KeyError(key)
    return default
```

```python
def setdefault(self, key, default=None):
    '''Insert key with a value of default if key is not in the dictionary.

    Return the value for key if key is in the dictionary, else default.
    '''
    if key in self:
        return self[key]
    self[key] = default
    return default
```

```python
@_recursive_repr()
def __repr__(self):
    'od.__repr__() <==> repr(od)'
    if not self:
        return '%s()' % (self.__class__.__name__,)
    return '%s(%r)' % (self.__class__.__name__, list(self.items()))
```

--------------------------------

### retrieve_by_specid(specid_list, svc='spectras', format='pkl', include='DEFAULT', dataset_list=None, limit=500, units=True, fmt=None, verbose=False)

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Retrieves spectra records from the SPARCL database by a list of specids.

```APIDOC
## retrieve_by_specid(specid_list, svc='spectras', format='pkl', include='DEFAULT', dataset_list=None, limit=500, units=True, fmt=None, verbose=False)

### Description
Retrieve spectra records from the SPARCL database by list of specids.

### Parameters
- **specid_list** (list) - Required - List of specids.
- **include** (list) - Optional - List of field names to include in each record. Defaults to 'DEFAULT'.
- **dataset_list** (list) - Optional - List of data sets from which to retrieve spectra data. Defaults to None.
- **limit** (int) - Optional - Maximum number of records to return. Defaults to 500.
- **units** (bool) - Optional - Set to True to include units in the header for each applicable field. Defaults to True.
- **fmt** (str) - Optional - Output format for the results. Defaults to None.
- **verbose** (bool) - Optional - Set to True for in-depth return statement. Defaults to False.

### Returns
- **Retrieved** (object) - Contains header and records, or a specutils/Pandas object if fmt is specified.
```

--------------------------------

### Internal Spectrum construction logic

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/specutils.html

This snippet demonstrates the internal logic for mapping SPARCL result attributes to a specutils Spectrum object.

```python
        redshift = r.redshift if 'redshift' in r else None
        uncertainty = InverseVariance(r.ivar) if 'ivar' in r else None
        mask = r.mask if 'mask' in r else None
        meta = {}
        for attribute in r:
            if attribute not in ('flux', 'wavelength', 'ivar',
                                 'redshift', 'mask'):
                value = r[attribute]
                unit_str = dr_units.get(attribute)
                if unit_str is not None:
                    try:
                        value = value * u.Unit(unit_str)
                    except (ValueError, TypeError):
                        pass
                meta[attribute] = value

        s1 = Spectrum(flux=r.flux * u.Unit(flux_unit),
                      spectral_axis=r.wavelength * u.Unit(wave_unit),
                      uncertainty=uncertainty,
                      redshift=redshift,
                      mask=mask,
                      meta=meta)
        s.append(s1)
    return s
```

--------------------------------

### SparclClient.login() / SparclClient.logout()

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Manages user authentication sessions for the SPARCL client.

```APIDOC
## SparclClient.login() / SparclClient.logout()

### Description
Handles authentication tokens to establish or terminate a session with the SPARCL API.
```

--------------------------------

### UserList Method Implementations

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Internal methods for managing data within a UserList-like structure.

```python
    def count(self, item):
        return self.data.count(item)

    def index(self, item, *args):
        return self.data.index(item, *args)

    def reverse(self):
        self.data.reverse()

    def sort(self, /, *args, **kwds):
        self.data.sort(*args, **kwds)

    def extend(self, other):
        if isinstance(other, UserList):
            self.data.extend(other.data)
        else:
            self.data.extend(other)
```

--------------------------------

### Retrieve All Fields

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Fetch fields tagged as 'all' from the SPARCL database.

```python
>>> client = SparclClient(announcement=False)
>>> client.get_all_fields()
['data_release', 'datasetgroup', 'dateobs', 'dateobs_center', 'dec', 'exptime', 'flux', 'instrument', 'ivar', 'mask', 'model', 'ra', 'redshift', 'redshift_err', 'redshift_warning', 'site', 'sparcl_id', 'specid', 'specprimary', 'spectype', 'survey', 'targetid', 'telescope', 'wave_sigma', 'wavelength', 'wavemax', 'wavemin']
```

--------------------------------

### UserDict Method Implementations

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Core methods for a UserDict wrapper, including iteration, containment, representation, and dictionary-like merge operations.

```python
def __iter__(self):
        return iter(self.data)

    # Modify __contains__ to work correctly when __missing__ is present
    def __contains__(self, key):
        return key in self.data

    # Now, add the methods in dicts but not in MutableMapping
    def __repr__(self):
        return repr(self.data)

    def __or__(self, other):
        if isinstance(other, UserDict):
            return self.__class__(self.data | other.data)
        if isinstance(other, dict):
            return self.__class__(self.data | other)
        return NotImplemented

    def __ror__(self, other):
        if isinstance(other, UserDict):
            return self.__class__(other.data | self.data)
        if isinstance(other, dict):
            return self.__class__(other | self.data)
        return NotImplemented

    def __ior__(self, other):
        if isinstance(other, UserDict):
            self.data |= other.data
        else:
            self.data |= other
        return self

    def __copy__(self):
        inst = self.__class__.__new__(self.__class__)
        inst.__dict__.update(self.__dict__)
        # Create a copy and avoid triggering descriptors
        inst.__dict__["data"] = self.__dict__["data"].copy()
        return inst

    def copy(self):
        if self.__class__ is UserDict:
            return UserDict(self.data.copy())
        import copy
        data = self.data
        try:
            self.data = {}
            c = copy.copy(self)
        finally:
            self.data = data
        c.update(self)
        return c

    @classmethod
    def fromkeys(cls, iterable, value=None):
        d = cls()
        for key in iterable:
            d[key] = value
        return d
```

--------------------------------

### SparclClient.find(outfields=None, constraints={}, limit=500, sort=None, units=True, fmt=None, verbose=False)

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Queries the SPARC database for records based on specified constraints and output fields. Returns a Found object or a Pandas DataFrame.

```APIDOC
## Method: SparclClient.find

### Description
Queries the SPARC database for records. Users can filter results using constraints, limit the number of records returned, and specify the output format.

### Parameters
- **outfields** (list, optional) - List of fields to return. Defaults to None (returns sparcl_id and _dr).
- **constraints** (dict, optional) - Key-Value pairs of constraints for record selection. Key is the field name, Value is a list of values.
- **limit** (int, optional) - Maximum number of records to return. Defaults to 500.
- **sort** (list, optional) - Comma separated list of fields to sort by.
- **units** (bool, optional) - Include units in the header. Defaults to True.
- **fmt** (str, optional) - Output format. Use 'pandas' for a DataFrame, otherwise returns a Found object.
- **verbose** (bool, optional) - Set to True for in-depth return statements. Defaults to False.

### Returns
- **Found** (object) - Contains header and records, or a Pandas DataFrame if fmt='pandas' is specified.

### Example
```python
client = SparclClient(announcement=False)
outs = ['sparcl_id', 'ra', 'dec']
cons = {'spectype': ['GALAXY'], 'redshift': [0.5, 0.9]}
found = client.find(outfields=outs, constraints=cons)
```
```

--------------------------------

### retrieve(uuid_list, include=None, dataset_list=None, limit=500, units=True, fmt=None, verbose=False)

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Retrieves spectra records from the SPARCL database using a list of sparcl_ids.

```APIDOC
## retrieve(uuid_list, include=None, dataset_list=None, limit=500, units=True, fmt=None, verbose=False)

### Description
Retrieves spectra records from the SPARCL database by a list of sparcl_ids.

### Parameters
- **uuid_list** (list) - Required - List of sparcl_ids.
- **include** (list) - Optional - List of field names to include in each record. Defaults to 'DEFAULT'.
- **dataset_list** (list) - Optional - List of data sets from which to retrieve spectra data. Defaults to None.
- **limit** (int) - Optional - Maximum number of records to return. Defaults to 500. Maximum allowed is 24,000.
- **units** (bool) - Optional - Set to True to include units in the header for each applicable field. Defaults to True.
- **fmt** (str) - Optional - Output format for the results ('specutils', 'pandas', or None). Defaults to None.
- **verbose** (bool) - Optional - Set to True for in-depth return statement. Defaults to False.

### Returns
- **Retrieved** (object) - Contains header and records, or a specutils/Pandas object if fmt is specified.
```

--------------------------------

### retrieve(uuid_list, include='DEFAULT', dataset_list=None, limit=500, units=True, fmt=None, verbose=False)

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Retrieves spectra records from the SPARCL database by a list of sparcl_ids.

```APIDOC
## retrieve(uuid_list, include='DEFAULT', dataset_list=None, limit=500, units=True, fmt=None, verbose=False)

### Description
Retrieve spectra records from the SPARCL database by list of sparcl_ids.

### Parameters
- **uuid_list** (list) - Required - List of sparcl_ids.
- **include** (list) - Optional - List of field names to include in each record. Defaults to 'DEFAULT'.
- **dataset_list** (list) - Optional - List of data sets from which to retrieve spectra data. Defaults to None (all data sets).
- **limit** (int) - Optional - Maximum number of records to return. Defaults to 500. Maximum allowed is 24,000.
- **units** (bool) - Optional - Set to True to include units in the header for each applicable field. Defaults to True.
- **fmt** (str) - Optional - Output format for the results. Options: 'specutils', 'pandas', or None (default).
- **verbose** (bool) - Optional - Set to True for in-depth return statement. Defaults to False.

### Returns
- **Results.Retrieved** (object) - Contains header and records, unless fmt='specutils' or fmt='pandas' is specified, in which case a specutils or Pandas Dataframe object is returned.
```

--------------------------------

### Data Retrieval and Request Handling

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

This snippet handles the logic for validating fields, constructing the API request, executing the POST request, and parsing the response in JSON or pickle format.

```python
        if (include == DEFAULT) or (include is None) or include == []:
            include_list = self.get_default_fields(dataset_list=dataset_list)
        elif include == ALL:
            include_list = self.get_all_fields(dataset_list=dataset_list)
        else:
            include_list = include

        self._validate_include(include_list, dataset_list)
        # Ensure 'sparcl_id' and 'specid' are always included
        for required in ("sparcl_id", "specid"):
            if required not in include_list:
                include_list.append(required)

        req_num = min(len(uuid_list), (limit or len(uuid_list)))
        #! print(f'DBG: req_num = {req_num:,d}'
        #!       f'  len(uuid_list)={len(uuid_list):,d}'
        #!       f'  limit={limit}'
        #!       f'  MAX_NUM_RECORDS_RETRIEVED={MAX_NUM_RECORDS_RETRIEVED:,d}')
        if req_num > MAX_NUM_RECORDS_RETRIEVED:
            msg = (
                f"Too many records asked for with client.retrieve()."
                f"  {len(uuid_list):,d} IDs provided,"
                f"  limit={limit}."
                f"  But the maximum allowed is"
                f" {MAX_NUM_RECORDS_RETRIEVED:,d}."
            )
            raise ex.TooManyRecords(msg)

        com_include = self._common_internal(
            science_fields=include_list, dataset_list=dataset_list
        )
        uparams = {
            "include": ",".join(com_include),
            # limit=limit,  # altered uuid_list to reflect limit
            #! "chunk_len": chunk,
            "format": format,
            #! "1thread": "yes",  # @@@ 7.3.2023
            #!"dataset_list": ",".join(dataset_list),
        }
        if not units:
            uparams["units"] = False

        # Do not put dataset_list in server call if it wasn't in client call.
        # Else will interfer with defaulting behavior of AUTH (DLS-504).
        if orig_dataset_list is not None:
            uparams["dataset_list"] = ",".join(dataset_list)

        qstr = urlencode(uparams)

        #!url = f'{self.apiurl}/retrieve/?{qstr}'
        url = f"{self.apiurl}/{svc}/?{qstr}"
        if verbose:
            print(f'Using url="{url}"')
            ut.tic()

        ids = list(uuid_list) if limit is None else list(uuid_list)[:limit]
        if self.show_curl:
            cmd = ut.curl_retrieve_str(ids, self.rooturl, svc=svc, qstr=qstr)
            print(cmd)

        try:
            auth = TokenAuth(self.token, self.token_expired) if self.token else None  # noqa: E501
            res = requests.post(url, json=ids, auth=auth, timeout=self.timeout)
        except requests.exceptions.ConnectTimeout as reCT:
            raise ex.UnknownSparcl(f"ConnectTimeout: {reCT}")
        except requests.exceptions.ReadTimeout as reRT:
            msg = (
                f'Try increasing the value of the "read_timeout" parameter'
                f' to "SparclClient()".'
                f" The current values is: {self.r_timeout} (seconds)"
                f"{reRT}"
            )
            raise ex.ReadTimeout(msg) from None
        except requests.exceptions.ConnectionError as reCE:
            raise ex.UnknownSparcl(f"ConnectionError: {reCE}")
        except requests.exceptions.TooManyRedirects as reTMR:
            raise ex.UnknownSparcl(f"TooManyRedirects: {reTMR}")
        except requests.exceptions.HTTPError as reHTTP:
            raise ex.UnknownSparcl(f"HTTPError: {reHTTP}")
        except requests.exceptions.URLRequired as reUR:
            raise ex.UnknownSparcl(f"URLRequired: {reUR}")
        except requests.exceptions.RequestException as reRE:
            raise ex.UnknownSparcl(f"RequestException: {reRE}")
        except Exception as err:  # fall through
            raise ex.UnknownSparcl(err)

        if verbose:
            elapsed = ut.toc()
            print(f"Got response to post in {elapsed} seconds")
        if res.status_code != 200:
            if verbose:
                print(f"DBG: Server response=\n{res.text}")
            # @@@ FAILS on invalid JSON. Maybe not json at all !!!
            if verbose and ("traceback" in res.json()):
                print(f"DBG: Server traceback=\n{res.json()['traceback']}")
            raise ex.genSparclException(res, verbose=verbose)

        if format == "json":
            results = res.json()
        elif format == "pkl":
            # Read chunked binary file (representing pickle file) from
            # server response. Load pickle into python data structure.
            # Python structure is list of records where first element
            # is a header.
            with tempfile.TemporaryFile(mode="w+b") as fp:
                for idx, chunk in enumerate(res.iter_content(chunk_size=None)):
                    fp.write(chunk)
                # Position to start of file for pickle reading (load)
                fp.seek(0)
                results = pickle.load(fp)
        else:
            results = res.json()
```

--------------------------------

### Counter utility methods

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Standard utility methods for copying, reducing, and deleting items from a Counter.

```python
    def copy(self):
        'Return a shallow copy.'
        return self.__class__(self)

    def __reduce__(self):
        return self.__class__, (dict(self),)

    def __delitem__(self, elem):
        'Like dict.__delitem__() but does not raise KeyError for missing values.'
        if elem in self:
            super().__delitem__(elem)
```

--------------------------------

### Bin spectra records

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/Results.html

Aligns flux from all records by a common wavelength bin, returning a 2D flux array and 1D wavelength array.

```python
>>> client = sparcl.client.SparclClient()
>>> found = client.find(
                constraints={"data_release": ['BOSS-DR16']},
                limit=10)
>>> got = client.retrieve(found.ids)
>>> flux2d,wavs = got.bin_spectra()
```

--------------------------------

### Defining default units

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/specutils.html

Sets the fallback units for flux and wavelength when header information is missing.

```python
# Default units used as fallback when results have no header (e.g. bare
# dict or _AttrDict records passed directly to conversion functions).
DEFAULT_FLUX_UNIT = '10**-17 erg cm-2 s-1 AA-1'
DEFAULT_WAVE_UNIT = 'AA'
```

--------------------------------

### Retrieve records from SPARCL database

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

This snippet demonstrates the internal logic for finding and retrieving records based on provided constraints and identifiers.

```python
# Science Field Name for uuid.
dr = list(self.fields.all_drs)[0]
idfld = self.fields._science_name("sparcl_id", dr)

found = self.find([idfld], constraints=constraints, limit=limit)
if verbose:
    print(f"Found {found.count} matches.")
if found.count < len(specid_list):
    usrcount = len(specid_list)
    dbcount = found.count
    warn = (
        f"UserWarning: Some SPECIDs were not found. "
        f"{usrcount - dbcount} out of the {usrcount} requested "
        f"uuids have no records available in the SPARCL database "
        f"associated with DataSets {dr_list}."
    )
    print(warn)
res = self.retrieve(
    found.ids,
    #! svc=svc,
    #! format=format,
    include=include,
    dataset_list=dataset_list,
    limit=limit,
    units=units,
    fmt=fmt,
    verbose=verbose,
)
if verbose:
    print(f"Got {res.count} records.")
return res
```

--------------------------------

### Implement TokenAuth for requests

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Custom authentication class that attaches a token to request headers and checks for renewal.

```python
class TokenAuth(AuthBase):
    """Attaches HTTP Token Authentication to the given Request object."""

    def __init__(self, token, renew_check):
        # setup any auth-related data here
        self.token = token
        self.renew_check = renew_check  # SparcClient Method

    def __call__(self, request):
        # modify and return the request
        # check and renew token if needed
        self.renew_check(renew=True)
        request.headers["Authorization"] = self.token
        return request
```

--------------------------------

### Convert field names between internal and science formats

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/Results.html

Methods to map record keys between internal and science-specific naming conventions. Note that to_science_fields modifies the internal records list in-place.

```python
    # Convert Internal field names to Science field names.
    # SIDE-EFFECT: modifies self.recs
    def to_science_fields(self):  # from_orig
        newrecs = list()
        for rec in self.recs:
            newrec = dict()
            dr = rec["_dr"]
            keep = True
            for orig in rec.keys():
                if orig == "_dr":
                    # keep DR around unchanged. We need it to rename back
                    # to Internal Field Names later.
                    newrec[orig] = rec[orig]
                else:
                    new = self.fields._science_name(orig, dr)
                    if new is None:
                        keep = False  # We don't have name mapping, toss rec
                    newrec[new] = rec[orig]
            if keep:
                newrecs.append(_AttrDict(newrec))
        self.recs = newrecs
```

```python
    # Convert Science field names to Internal field names.
    def to_internal_fields(self):
        for rec in self.recs:
            dr = rec.get("_dr")
            for new in rec.keys():
                if new == "_dr":
                    # keep DR around unchanged. We need it to rename back
                    # to Internal Field Names later.
                    continue
                new = self.fields._internal_name(new, dr)
                rec[new] = rec.pop(new)
```

```python
    def science_to_internal_fields(self):
        newrecs = list()
        for rec in self.recs:
            newrec = dict()
            dr = rec["_dr"]
            keep = True
            for sci_name in rec.keys():
                if sci_name == "_dr":
                    # keep DR around unchanged. We need it to rename back
                    # to Internal Field Names later.
                    newrec[sci_name] = rec[sci_name]
                else:
                    new = self.fields._internal_name(sci_name, dr)
                    if new is None:
                        keep = False
                    newrec[new] = rec[sci_name]
            if keep:
                newrecs.append(_AttrDict(newrec))
        self.recs = newrecs
        return self.recs
```

--------------------------------

### SparclClient.login

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/client.html

Authenticates the user with the SPARCL service using an email and password to obtain an access token.

```APIDOC
## login(email, password=None)

### Description
Authenticates the user with the SPARCL service. If the password is not provided, it will be prompted via standard input.

### Parameters
- **email** (str) - Required - The user's email address.
- **password** (str) - Optional - The user's password.

### Returns
- **None** (None) - Returns None on success.
- **str** (str) - Returns an error message if authentication fails.
```

--------------------------------

### Login to SPARCL

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Authenticates the user with the SPARCL service using an email and password.

```python
>>>
>> client = SparclClient(announcement=False)
>> client.login('test_user@noirlab.edu', 'testpw')
Logged in successfully with email='test_user@noirlab.edu'
```

--------------------------------

### Retrieve field units from SPARCL results

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/Results.html

Demonstrates how to look up unit strings for specific fields, optionally filtered by data release.

```python
>>> results.unit_for('flux')
'1e-17 erg cm-2 s-1 AA-1'
>>> results.unit_for('wave_sigma')
{'SDSS-DR17': 'pixel', 'DESI-DR1': 'AA'}
>>> results.unit_for('dec', data_release='DESI-DR1')
'deg'
```

--------------------------------

### Define OrderedDict and internal helper classes

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Implementation of OrderedDict and its associated view and link classes for maintaining insertion order.

```python
class _OrderedDictKeysView(_collections_abc.KeysView):

    def __reversed__(self):
        yield from reversed(self._mapping)

class _OrderedDictItemsView(_collections_abc.ItemsView):

    def __reversed__(self):
        for key in reversed(self._mapping):
            yield (key, self._mapping[key])

class _OrderedDictValuesView(_collections_abc.ValuesView):

    def __reversed__(self):
        for key in reversed(self._mapping):
            yield self._mapping[key]

class _Link(object):
    __slots__ = 'prev', 'next', 'key', '__weakref__'

class OrderedDict(dict):
    'Dictionary that remembers insertion order'
    # An inherited dict maps keys to values.
    # The inherited dict provides __getitem__, __len__, __contains__, and get.
    # The remaining methods are order-aware.
    # Big-O running times for all methods are the same as regular dictionaries.

    # The internal self.__map dict maps keys to links in a doubly linked list.
    # The circular doubly linked list starts and ends with a sentinel element.
    # The sentinel element never gets deleted (this simplifies the algorithm).
    # The sentinel is in self.__hardroot with a weakref proxy in self.__root.
    # The prev links are weakref proxies (to prevent circular references).
    # Individual links are kept alive by the hard reference in self.__map.
    # Those hard references disappear when a key is deleted from an OrderedDict.

    def __init__(self, other=(), /, **kwds):
        '''Initialize an ordered dictionary.  The signature is the same as
        regular dictionaries.  Keyword argument order is preserved.
        '''
        try:
            self.__root
        except AttributeError:
            self.__hardroot = _Link()
            self.__root = root = _proxy(self.__hardroot)
            root.prev = root.next = root
            self.__map = {}
        self.__update(other, **kwds)

    def __setitem__(self, key, value,
                    dict_setitem=dict.__setitem__, proxy=_proxy, Link=_Link):
        'od.__setitem__(i, y) <==> od[i]=y'
        # Setting a new item creates a new link at the end of the linked list,
        # and the inherited dictionary is updated with the new key/value pair.
        if key not in self:
            self.__map[key] = link = Link()
            root = self.__root
            last = root.prev
            link.prev, link.next, link.key = last, root, key
            last.next = link
            root.prev = proxy(link)
        dict_setitem(self, key, value)

    def __delitem__(self, key, dict_delitem=dict.__delitem__):
        'od.__delitem__(y) <==> del od[y]'
        # Deleting an existing item uses self.__map to find the link which gets
        # removed by updating the links in the predecessor and successor nodes.
        dict_delitem(self, key)
        link = self.__map.pop(key)
        link_prev = link.prev
        link_next = link.next
        link_prev.next = link_next
        link_next.prev = link_prev
        link.prev = None
        link.next = None
```

--------------------------------

### SparclClient.find()

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Searches for datasets or records within the SPARCL system.

```APIDOC
## SparclClient.find()

### Description
Performs a search operation to find records or datasets based on specified constraints.

### Method
Python SDK Method

### Parameters
- **args/kwargs** - Search constraints and query parameters as defined by the SPARCL service.
```

--------------------------------

### Counter representation

Source: https://sparclclient.readthedocs.io/en/latest/_modules/collections.html

Returns a string representation of the Counter instance.

```python
    def __repr__(self):
        if not self:
            return f'{self.__class__.__name__}()'
        try:
            # dict() preserves the ordering returned by most_common()
            d = dict(self.most_common())
        except TypeError:
            # handle case where values are not orderable
            d = dict(self)
        return f'{self.__class__.__name__}({d!r})'
```

--------------------------------

### to_Spectrum

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/specutils.html

Converts retrieved results into a specutils Spectrum or SpectrumCollection object.

```APIDOC
## to_Spectrum(results, *, collection=False, flux_unit=None, wave_unit=None)

### Description
Converts retrieved results into a specutils Spectrum or SpectrumCollection object.

### Parameters
- **results** (sparcl.Results.Retrieved) - Required - Retrieved results, or a single record from a set of results.
- **collection** (bool) - Optional - If True, attempt to convert to a specutils.SpectrumCollection instead.
- **flux_unit** (str) - Optional - Unit string for flux. If None, resolved via _get_units().
- **wave_unit** (str) - Optional - Unit string for wavelength. If None, resolved via _get_units().

### Returns
- **Spectrum or SpectrumCollection** - The requested spectral object.
```

--------------------------------

### get_available_fields()

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Retrieves a list of all available fields for specified datasets.

```APIDOC
## get_available_fields(dataset_list=None)

### Description
Returns the intersection of all available fields across the provided dataset list, or all datasets if none are specified.

### Parameters
- **dataset_list** (list) - Optional - List of data sets to query.
```

--------------------------------

### Convert SPARCL results to SpectrumList

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/specutils.html

Converts retrieved SPARCL results into a specutils SpectrumList object.

```python
[docs]
def to_SpectrumList(results, *, flux_unit=None, wave_unit=None):
    """Convert `results` to :class:`specutils.SpectrumList`.

    Parameters
    ----------
    results : :class:`sparcl.Results.Retrieved`
        Retrieved results.
    flux_unit : str, optional
        Unit string for flux. If None, resolved via _get_units().
    wave_unit : str, optional
        Unit string for wavelength. If None, resolved via _get_units().

    Returns
    -------
    :class:`~specutils.SpectrumList`
        The requested object.
    """
    if flux_unit is None or wave_unit is None:
        flux_unit, wave_unit = _get_units(results)

    s = SpectrumList()
    if isinstance(results, dict):
        records = [results]
    else:
        records = results.records
    for r in records:
        dr_units = {}
        if hasattr(results, 'hdr'):
            try:
                dr = r.get('_dr')
                dr_units = results.hdr.get('UNITS', {}).get(dr, {})
            except (AttributeError, KeyError):
                pass
```

--------------------------------

### get_all_fields()

Source: https://sparclclient.readthedocs.io/en/latest/sparcl.html

Retrieves a list of fields tagged as 'all' for specified datasets.

```APIDOC
## get_all_fields(dataset_list=None)

### Description
Returns the intersection of all fields tagged as 'all' across the provided dataset list, or all datasets if none are specified.

### Parameters
- **dataset_list** (list) - Optional - List of data sets to query.
```

--------------------------------

### Convert results to specutils

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/Results.html

Converts the current results object into a specutils Spectrum object.

```python
def to_specutils(self):
    """Convert results to a `specutils` object.

    Returns:
        to_specutils (:class:`~specutils.Spectrum`): a `specutils` object.
    """
    return su.to_specutils(self)
```

--------------------------------

### Results.to_specutils()

Source: https://sparclclient.readthedocs.io/en/latest/_modules/sparcl/Results.html

Converts the results object into a specutils Spectrum object.

```APIDOC
## Results.to_specutils()

### Description
Converts the current results into a `specutils.Spectrum` object.

### Returns
- **to_specutils** (specutils.Spectrum) - A specutils object containing the spectral data.
```