code: def has_in_collaborators(self, collaborator):
          
          assert isinstance(collaborator, github.NamedUser.NamedUser) or isinstance(collaborator, (str, unicode)), collaborator
  
          if isinstance(collaborator, github.NamedUser.NamedUser):
              collaborator = collaborator._identity
  
          status, headers, data = self._requester.requestJson(
              "GET",
              self.url + "/collaborators/" + collaborator
          )
          return status == 204
docs: :calls: `GET /repos/:owner/:repo/collaborators/:user <http://developer.github.com/v3/repos/collaborators>`_
          :param collaborator: string or :class:`github.NamedUser.NamedUser`
          :rtype: bool