code: def __init__(self, filename):
      model = graph_pb2.GraphDef()
      load_protobuf_from_file(model, filename)
      super(IRGraph, self).__init__(model)
  
imports: import mmdnn.conversion.common.IR.graph_pb2
  from mmdnn.conversion.common.utils import *
  from mmdnn.conversion.common.IR.graph_pb2 import TensorShape, AttrValue
  from mmdnn.conversion.common.DataStructure.graph import Graph, GraphNode
label_desc: Use image node_id 2 to create a new IRGraph object from inherited base classes: Graph with example: obj = IRGraph(filename)