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 get_date(self, p_tag):
        """ Given a date tag, return a date object. """
        string = self.tag_value(p_tag)
        result = None

        try:
            result = date_string_to_date(string) if string else None
        except ValueError:
            pass

        return result