code: def backend(self, client=None):
          '''The :class:`stdnet.BackendDatServer` for this instance.
  
          It can be ``None``.
          '''
          session = self.session
          if session:
              return session.model(self).backenf backend(self, client=None):
          '''The :class:`stdnet.BackendDatServer` for this instance.
  
          It can be ``None``.
          '''
          session = self.session
          if session:
              return session.model(self).backend
docs: The :class:`stdnet.BackendDatServer` for this instance.
  
          It can be ``None``.