code: def call(self, x1, x2):
      y1 = self.conv_bn_1(x1)
      y2 = self.conv_bn_2(x2)
      y = F.concatenate(y1, y2, axis=1)
      return y
  
imports: import os
  import io
  import pytest
  import numpy
  import nnabla
  import nnabla.functions
  import nnabla.parametric_functions
  from collections import OrderedDict
  from nnabla.testing import assert_allclose
  from nnabla.core.modules import ConvBn, ResUnit
  from helper import ModuleCreator, forward_variable_and_check_equal, create_temp_with_dir
label_desc: Use image node_id 2 for calling the TSTNetNormal obj's underlying member method code with example usage: obj.call(x1, x2) and returns: y