code: def __call__(self, n_id):
      producer = self.produce_subgraph
      return producer(n_id)
  
file_path: euler/tf_euler/python/dataflow/relation_dataflow.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
  import tf_euler
  from tf_euler.python.dataflow.base_dataflow import DataFlow
label_desc: Use image node_id 4 for calling the RelationDataFlow obj's underlying member method code with example usage: obj.__call__(n_id) and returns: producer