def contains(
        self, item: UnparsedVersion, prereleases: Optional[bool] = None
    ) -> bool:
        """Return whether or not the item is contained in this specifier.

        :param item:
            The item to check for, which can be a version string or a
            :class:`Version` instance.
        :param prereleases:
            Whether or not to match prereleases with this Specifier. If set to
            ``None`` (the default), it uses :attr:`prereleases` to determine
            whether or not prereleases are allowed.

        >>> Specifier(">=1.2.3").contains("1.2.3")
        True
        >>> Specifier(">=1.2.3").contains(Version("1.2.3"))
        True
        >>> Specifier(">=1.2.3").contains("1.0.0")
        False
        >>> Specifier(">=1.2.3").contains("1.3.0a1")
        False
        >>> Specifier(">=1.2.3", prereleases=True).contains("1.3.0a1")
        True
        >>> Specifier(">=1.2.3").contains("1.3.0a1", prereleases=True)
        True
        """

        # Determine if prereleases are to be allowed or not.
        if prereleases is None:
            prereleases = self.prereleases

        # Normalize item to a Version, this allows us to have a shortcut for
        # "2.0" in Specifier(">=2")
        normalized_item = _coerce_version(item)

        # Determine if we should be supporting prereleases in this specifier
        # or not, if we do not support prereleases than we can short circuit
        # logic if this version is a prereleases.
        if normalized_item.is_prerelease and not prereleases:
            return False

        # Actually do the comparison to determine if this item is contained
        # within this Specifier or not.
        operator_callable: CallableOperator = self._get_operator(self.operator)
        return operator_callable(normalized_item, self.version)
Return whether or not the item is contained in this specifier.

        :param item:
            The item to check for, which can be a version string or a
            :class:`Version` instance.
        :param prereleases:
            Whether or not to match prereleases with this Specifier. If set to
            ``None`` (the default), it uses :attr:`prereleases` to determine
            whether or not prereleases are allowed.

        >>> Specifier(">=1.2.3").contains("1.2.3")
        True
        >>> Specifier(">=1.2.3").contains(Version("1.2.3"))
        True
        >>> Specifier(">=1.2.3").contains("1.0.0")
        False
        >>> Specifier(">=1.2.3").contains("1.3.0a1")
        False
        >>> Specifier(">=1.2.3", prereleases=True).contains("1.3.0a1")
        True
        >>> Specifier(">=1.2.3").contains("1.3.0a1", prereleases=True)
        True
        
product/gradle-plugin/src/main/python/pkg_resources/_vendor/packaging/specifiers.py