code: def fit(self, X, y=None, **fit_params):
          
          self.estimator.fit(X, y, **fit_params)
          return self
docs: Fit the StackingEstimator meta-transformer.
  
          Parameters
          ----------
          X: array-like of shape (n_samples, n_features)
              The training input samples.
          y: array-like, shape (n_samples,)
              The target values (integers that correspond to classes in classification, real numbers in regression).
          fit_params:
              Other estimator-specific parameters.
  
          Returns
          -------
          self: object
              Returns a copy of the estimator