:calls: `POST /repos/:owner/:repo/git/refs <http://developer.github.com/v3/git/refs>`_
        :param ref: string
        :param sha: string
        :rtype: :class:`github.GitRef.GitRef`

def create_git_ref(self, ref, sha):
        """
        :calls: `POST /repos/:owner/:repo/git/refs <http://developer.github.com/v3/git/refs>`_
        :param ref: string
        :param sha: string
        :rtype: :class:`github.GitRef.GitRef`
        """
        assert isinstance(ref, (str, unicode)), ref
        assert isinstance(sha, (str, unicode)), sha
        post_parameters = {
            "ref": ref,
            "sha": sha,
        }
        headers, data = self._requester.requestJsonAndCheck(
            "POST",
            self.url + "/git/refs",
            input=post_parameters
        )
        return github.GitRef.GitRef(self._requester, headers, data, completed=True)