code: def train(self, ds):
          
          if self.useErrors:
              self.coeffs, self.scatters, self.new_tr_labels, self.chisqs, self.pivots, self.scales = _train_model_new(ds)
          else:
              self.coeffs, self.scatters, self.chisqs, self.pivots, self.scales = _train_model(ds)
docs: Run training step: solve for best-fit spectral model