code: def double_matmul():
      model = ModelHelper(name="r")
      fc0 = brew.fc(model, "data", "fc0", 10, 10)
      fc1 = brew.fc(model, fc0, "fc1", 10, 10)
      model.Proto().external_output[:] = [str(fc0), str(fc1)]
      return model, [(1, 10)]
  
imports: import unittest
  import numpy
  import copy
  from hypothesis import given
  import hypothesis.strategies
  from caffe2.python.model_helper import ModelHelper
  from caffe2.python.models import resnet
  from caffe2.python import workspace, brew
  import caffe2.python.hypothesis_test_util
  import caffe2.python.mkl.rewrite_graph
label_desc: Use image node_id 3 for calling a global function with example usage: double_matmul() and returns: model,  list