code: def _update_field(self, natvalue):
          
          updated = False
          if natvalue.element and natvalue.element != self.element:
              self.update(element=natvalue.element)
              self.pop('ip_descriptor', None)
              updated = True
          elif natvalue.ip_descriptor and self.ip_descriptor and \
              natvalue.ip_descriptor != self.ip_descriptor:
              self.update(ip_descriptor=natvalue.ip_descriptor)
              self.pop('element', None)
              updated = True
  
          for port in ('min_port', 'max_port'):
              _port = getattr(natvalue, port, None)
              if _port is not None and getattr(self, port, None) != _port:
                  self[port] = _port
                  updated = True
      
          return updated
docs: Update this NATValue if values are different
          
          :rtype: bool