code: def fit(self, X, y=None):
          
          if self.degree_range is not None:
              self.degree = self.baart_criteria(X, y)
          return self
docs: Sets *self.degree* according to :func:`baart_criteria` if *degree_range*
          is not None, otherwise does nothing.
  
          **Parameters**
  
          X : array-like, shape = [n_samples, 1]
              Column vector of phases.
          y : array-like or None, shape = [n_samples], optional
              Row vector of magnitudes (default None).
  
          **Returns**
  
          self : returns an instance of self