### Python Environment Setup and SDK Installation

Source: https://github.com/square-developers/python-getting-started/blob/main/README.md

Commands to create a Python virtual environment, activate it, install project dependencies from requirements.txt, and install the Square Python SDK.

```shell
$ python3 -m venv env
$ source env/bin/activate
$ pip3 install -r requirements.txt
$ pip3 install squareup
```

```shell
# Optional: Install legacy SDK
$ pip3 install squareup_legacy
```

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

### Running the Square Python Quickstart Script

Source: https://github.com/square-developers/python-getting-started/blob/main/README.md

Command to execute the main Python script that utilizes the Square SDK after setup and configuration.

```shell
$ python3 ./quickstart.py
```

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

### Square Access Token Configuration

Source: https://github.com/square-developers/python-getting-started/blob/main/README.md

Configuration snippet for setting the Square API access token. This file should be named .env and kept secure.

```env
SQUARE_ACCESS_TOKEN=yourSandboxAccessToken
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.