code: def _build_extra_inputs(self, train=True):
      if train:
          self._add_input(
              name="labels", dtype="float32", shape=[self._batch_size]
          )
  
file_path: openrec/openrec/tf1/legacy/recommenders/pmf.py
imports: from openrec.tf1.legacy.recommenders import Recommender
  from openrec.tf1.legacy.modules.extractions import LatentFactor
  from openrec.tf1.legacy.modules.interactions import PointwiseMSE
label_desc: Use image node_id 5 for calling the PMF obj's underlying member method code with example usage: obj._build_extra_inputs(train) without return types