docs: def publish(self, user, provider, obj, comment, **kwargs):
          '''
              user - django User or UserSocialAuth instance
              provider - name of publisher provider
              obj - sharing object
              comment - string
          '''
          social_user = self._get_social_user(user, provider)
          backend = self.get_backend(social_user, provider, context=kwargs)
          return backend.publish(obj, comment)