code: def git_commit(self, sha):
          
          json = {}
          if sha:
              url = self._build_url('git', 'commits', sha, base_url=self._api)
              json = self._json(self._get(url), 200)
          return Commit(json, self) if json else None
docs: Get a single (git) commit.
  
          :param str sha: (required), sha of the commit
          :returns: :class:`Commit <github3.git.Commit>` if successful,
              otherwise None