docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'field') and self.field is not None:
              _dict['field'] = self.field
          if hasattr(self, 'interval') and self.interval is not None:
              _dict['interval'] = self.interval
          if hasattr(self, 'anomaly') and self.anomaly is not None:
              _dict['anomaly'] = self.anomaly
          return _dict