When converting a tensorflow model to a uff model, the dynamic_graph.collapse_namespaces(namespace_plugin_map, exclude_nodes=nodes) will cause an error: None is not iterable. I solve this by modifying the code as below.
In the file: /usr/local/lib/python3.5/dist-packages/graphsurgeon/DynamicGraph.py
def get_plugin_node(node_name): # Get the default plugin node provided by the user, or return None if this # does not belong in a plugin. if node_name in exclude_node_names: # Don't put this node into a plugin, treat as normal node instead. return None, None