docs: def get_collaborator_permission(self, collaborator):
          """
          :calls: `GET /repos/:owner/:repo/collaborators/:username/permission <http://developer.github.com/v3/repos/collaborators>`_
          :param collaborator: string or :class:`github.NamedUser.NamedUser`
          :rtype: string
          """
          assert isinstance(collaborator, github.NamedUser.NamedUser) or isinstance(collaborator, (str, unicode)), collaborator
          if isinstance(collaborator, github.NamedUser.NamedUser):
              collaborator = collaborator._identity
          headers, data = self._requester.requestJsonAndCheck(
              "GET",
              self.url + "/collaborators/" + collaborator + "/permission",
          )
          return data["permission"]