code: def to_onnx_graph(self):
      for node in self.function_nodes:
          self.convert_to_onnx_node(node)
  
file_path: chainer/onnx_chainer/graph.py
imports: import collections
  from collections import OrderedDict
  import heapq
  import chainer
  from onnx_chainer.functions.converter import FunctionConverterParams
  from onnx_chainer import onnx_helper
label_desc: Use image node_id 5 for calling the Graph obj's underlying member method code with example usage: obj.to_onnx_graph() without return types