the nodes in matched_subgraph_pairs.

            An example successful test case:

              matched_subgraph_pairs = {'x0': (graph_a_conv_0_node, graph_b_conv_0_node)}
              expected_types = {'x0': (nn.Conv2d, nnq.Conv2d)}

            The function tests for key equivalence, and verifies types with
            instance checks.
            rh