### PSR-11 Container Interface

Source: https://github.com/php-fig/container/blob/master/README.md

Defines the core interface for a PHP Dependency Injection Container as per PSR-11. It specifies methods for checking the existence of an entry and retrieving an entry by its identifier.

```php
<?php

namespace Psr\Container;

/**
 * Represents a container that can be resolved by a unique identifier.
 */
interface ContainerInterface
{
    /**
     * Finds an entry of the container by its identifier.
     *
     * @param string $id Identifier of the entry to look for.
     *
     * @return mixed
     *   The entry to be found.
     *
     * @throws NotFoundExceptionInterface
     *   No entry was found for **this** identifier, and **nothing** to fall back on.
     *
     * @throws ContainerExceptionInterface
     *   Error while retrieving the entry.
     */
    public function get(string $id);

    /**
     * Returns true if the container can return an entry for the given identifier,
     * and false if it cannot.
     *
     * @param string $id Identifier of the entry to look for.
     *
     * @return bool
     */
    public function has(string $id): bool;
}

```

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