code: def forward(self, x1, x2):
      out_fc1 = self.fc1(x1)
      out_fc2 = self.fc2(x2)
      out = mx.np.concatenate([out_fc1, out_fc2])
      out = mx.npx.softmax(out)
      return out
  
imports: import mxnet
  import numpy
  import unittest
  import pytest
  import ctypes
  import copy
  from mxnet.contrib import quantization
  from mxnet.gluon import nn
  from mxnet.test_utils import assert_almost_equal, assert_almost_equal_with_err
label_desc: Use image node_id 2 for calling the TailNegBlock obj's underlying member method code with example usage: obj.forward(x1, x2) and returns: out