code: def roles(self):
          
          if self._roles is None:
              self._roles = RoleList(self._version, service_sid=self._solution['sid'], )
          return self._roles
docs: Access the roles
  
          :returns: twilio.rest.chat.v2.service.role.RoleList
          :rtype: twilio.rest.chat.v2.service.role.RoleList