code: def build_user_features(self, data, normalize=True):
          
  
          builder = _FeatureBuilder(
              self._user_id_mapping,
              self._user_feature_mapping,
              self._user_identity_features,
              normalize,
              "user",
          )
  
          return builder.build(data)
docs: Build a user features matrix out of an iterable of the form
          (user id, [list of feature names]) or (user id, {feature name: feature weight}).
  
          Parameters
          ----------
  
          data: iterable of the form
              (user id, [list of feature names]) or (user id,
              {feature name: feature weight}).
              User and feature ids will be translated to internal indices
              constructed during the fit call.
          normalize: bool, optional
              If true, will ensure that feature weights sum to 1 in every row.
  
          Returns
          -------
  
          feature matrix: CSR matrix (num users, num features)
              Matrix of user features.