code: def _prepare_travel_graph(self):
      for op in self.op_dict.values():
          op.const = False
          if op.node.op in ["Const", "Placeholder"]:
              op.resolved = True
              if op.node.op == "Const":
                  op.const = True
          else:
              op.resolved = False
  
imports: import numpy
  import tensorflow.compat.v1
  from tensorflow.core.framework.tensor_pb2 import TensorProto
  from tensorflow.core.framework.tensor_shape_pb2 import TensorShapeProto
label_desc: Use image node_id 8 for calling the RefineGraph obj's underlying member method code with example usage: obj._prepare_travel_graph() without return types