Check GitHub for a release with the specified tag name. If present,
        return a 2-tuple of the release name and release HTML URL. Otherwise,
        return a 2-tuple of None, None (tag not present).

        :param version: the tag name to check for
        :type version: str
        :return: 2-tuple of release name, release HTML URL for the specified
          release tag, or 2-tuple of None, None if no such release
        :rtype: tuple

def get_tag(self, version):
        """
        Check GitHub for a release with the specified tag name. If present,
        return a 2-tuple of the release name and release HTML URL. Otherwise,
        return a 2-tuple of None, None (tag not present).

        :param version: the tag name to check for
        :type version: str
        :return: 2-tuple of release name, release HTML URL for the specified
          release tag, or 2-tuple of None, None if no such release
        :rtype: tuple
        """
        for rel in self._repo.releases():
            if rel.tag_name == version:
                return rel.name, rel.html_url
        return None, None