def get_git_ref(self, ref):
prefix = "<STR_LIT>"<EOL>if not self._requester.FIX_REPO_GET_GIT_REF:<EOL><INDENT>prefix = "<STR_LIT>"<EOL><DEDENT>assert isinstance(ref, (str, unicode)), ref<EOL>headers, data = self._requester.requestJsonAndCheck(<EOL>"<STR_LIT:GET>",<EOL>self.url + prefix + ref<EOL>)<EOL>return github.GitRef.GitRef(self._requester, headers, data, completed=True)<EOL>
:calls: `GET /repos/:owner/:repo/git/refs/:ref <http://developer.github.com/v3/git/refs>`_
:param ref: string
:rtype: :class:`github.GitRef.GitRef`