docs: def add_to_assignees(self, *assignees):
          """
          :calls: `POST /repos/:owner/:repo/issues/:number/assignees <https://developer.github.com/v3/issues/assignees>`_
          :param assignee: :class:`github.NamedUser.NamedUser` or string
          :rtype: None
          """
          assert all(isinstance(element, (github.NamedUser.NamedUser, str, unicode)) for element in assignees), assignees
          post_parameters = {"assignees": [assignee.login if isinstance(assignee, github.NamedUser.NamedUser) else assignee for assignee in assignees]}
          headers, data = self._requester.requestJsonAndCheck(
              "POST",
              self.url + "/assignees",
              input=post_parameters
          )
          self._useAttributes(data)