Same issue has been reported via https://developer.nvidia.com.
Bug ID: 2541496
[Platform details]
graphsurgeon-tf_5.1.2-1+cuda9.0_amd64.deb
Line 51 in “node_manipulation.py” in “graphsurgeon-tf_5.1.2-1+cuda9.0_amd64.deb” should be
if isinstance(input_node, tf.NodeDef):
instead of
if isinstance(input_node, NodeDef):