code: def _process_graph(self):
          
          all_nodes = [x.name for x in self.graph.as_graph_def().node]
          nodes = [x for x in all_nodes if x in self.possible_output_nodes]
          logger.info('List of nodes to export for brain :' + self.brain.brain_name)
          for n in nodes:
              logger.info('\t' + n)
          return nodes
docs: Gets the list of the output nodes present in the graph for inference
          :return: list of node names