docs: def import_milestone(self, name, estimated_start, estimated_finish,
                           **attrs):
          """
          Import a Milestone and returns a :class:`Milestone` object.
  
          :param name: name of the :class:`Milestone`
          :param estimated_start: estimated start time of the
                                  :class:`Milestone`
          :param estimated_finish: estimated finish time of the
                                   :class:`Milestone`
          :param attrs: optional attributes for :class:`Milestone`
          """
          return Milestones(self.requester).import_(
              self.id, name, estimated_start,
              estimated_finish, **attrs
          )