code: def check_graph(self, graph: onnx.GraphProto) -> None:
      self.assertEqual(len(graph.node), 3)
      self.assertEqual(graph.node[0].op_type, "MatMul")
      self.assertEqual(graph.node[1].op_type, "Add")
      self.assertEqual(graph.node[2].op_type, "Softmax")
  
imports: import unittest
  import onnx
  from onnx import parser, printer
label_desc: Use image node_id 1 for calling the TestBasicFunctions obj's underlying member method code with example usage: obj.check_graph(graph) without return types