code: def json(self):
          
          return {
              "model_type": self.model_type,
              "formula": self.formula,
              "status": self.status,
              "model_params": self.model_params,
              "r_squared_adj": _noneify(self.r_squared_adj),
              "warnings": [w.json() for w in self.warnings],
          }
docs: Return a JSON-serializable representation of this result.
  
          The output of this function can be converted to a serialized string
          with :any:`json.dumps`.