code: def user_bindings(self):
          
          if self._user_bindings is None:
              self._user_bindings = UserBindingList(
                  self._version,
                  service_sid=self._solution['service_sid'],
                  user_sid=self._solution['sid'],
              )
          return self._user_bindings
docs: Access the user_bindings
  
          :returns: twilio.rest.chat.v2.service.user.user_binding.UserBindingList
          :rtype: twilio.rest.chat.v2.service.user.user_binding.UserBindingList