code: def get_feature_names(self):
          
          return ['temperature', 'pressure'] + [f'solvent.{x}' for x in range(1, self.max_solvents + 1)] + \
                 [f'solvent_amount.{x}' for x in range(1, self.max_solvents + 1)]
docs: Get feature names.
  
          Returns
          -------
          feature_names : list of strings
              Names of the features produced by transform.