class_docstr: GraphStream is a class for delta automatical optimization
code: def __enter__(self):
      self.__delta_graph_original = DeltaGraph(pb_file=self.__path)
      return self
  
file_path: delta/gcompiler/python/delta_infer/optimizer.py
imports: from __future__ import absolute_import, division, print_function
  import os
  import sys
  from .subgraphs import *
  from .cpp import DeltaGraph, AutoOptimizer, RegisterPattern
label_desc: Use image node_id 6 for calling the GraphStream obj's underlying member method code with example usage: obj.__enter__() and returns: self