code: def onnx_layer(self):
      return self.layer
  
file_path: MMdnn/mmdnn/conversion/onnx/onnx_graph.py
imports: from mmdnn.conversion.common.DataStructure.graph import GraphNode, Graph
  from onnx import onnx_pb2
label_desc: Use image node_id 4 for calling the ONNXGraphNode obj's underlying member method code with example usage: obj.onnx_layer() and returns: self