code: def nnp_get_topo(nnp, side, callback=None):
      for network_name in sorted(nnp.get_network_names()):
          network = nnp.get_network(
              network_name, batch_size=4, callback=callback
          )
          yield network
  
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  import nnabla.parametric_functions
  from nnabla.testing import assert_allclose
  from helper import get_saved_test_model, forward_variable_and_check_equal, forward_variable, assert_topology, dump_network_topology
  import legacy_nnp_graph
  from nnabla.utils import nnp_graph
label_desc: Use image node_id 4 for calling a global function with example usage: nnp_get_topo(nnp, side, callback) without return types