code: def predict(self, df):
      from mlflow.version import VERSION
  
      if self._check_version:
          assert VERSION == MLFLOW_VERSION
      mu = df.mean().mean()
      return [mu for _ in range(len(df))]
  
label_desc: Use image node_id 2 for calling the PyFuncTestModel obj's underlying member method code with example usage: obj.predict(df) and returns: unknown