/** @param Map<int, int|string> $a */
public function mapGetUnionType(Map $a) : void
{
	assertType('int|string', $a->get(0));
}

/**
 * @template TKey
 * @template TValue
 * @implements Collection<TKey, TValue>
 */
final class Map implements Collection
{
    /**
     * @param iterable<TKey, TValue>|null $values
     */
    public function __construct(?iterable $values = null)
    {
    }

/**
 * @template TDefault
 * @param TKey $key
 * @param TDefault $default
 * @return TValue|TDefault
 * @throws OutOfBoundsException
 */
public function get($key, $default = null)