def __init__(self, package, version):
        """Construct a new requirement.

        :param package: the package name.
        :param version: a semver compatible version specification.
        """
        self.package = package
        self.version = version
        if self.version and not re.match(r"[<=>~]", version[:2]):
            self.version = "=={}".format(self.version)
def __init__(self, directory=None):
        if directory is None:
                directory = []
        import copy
        self.directory = copy.deepcopy(directory)
        self.bound = False
        self.start_tls_called = False
        self.extend = self.Extend(self)

        self.operation = {
                    "!" : self._search_not,
                    "&" : self._search_and,
                    "|" : self._search_or,
            }