code: def get_commit(self, sha):
          
          assert isinstance(sha, (str, unicode)), sha
          headers, data = self._requester.requestJsonAndCheck(
              "GET",
              self.url + "/commits/" + sha
          )
          return github.Commit.Commit(self._requester, headers, data, completed=True)
docs: :calls: `GET /repos/:owner/:repo/commits/:sha <http://developer.github.com/v3/repos/commits>`_
          :param sha: string
          :rtype: :class:`github.Commit.Commit`