docstr: Test Fuse BN function.
docstr_tok: ["Test","Fuse","BN","function","."]
code: def test_double(self):
      """
      Test Fuse BN function.
      """
      conv = nn.Conv2d(
          in_channels=3,
          out_channels=6,
          kernel_size=1,
          stride=1,
          padding=0,
          dilation=1,
          groups=1,
      )
      bn = nn.BatchNorm2d(3)
      f = fuse_bn(conv, bn)
      # print(len(f), f[0].shape, f[1].shape)
      self.assertTrue(len(f) == 2)
      self.assertTrue(f[0].shape == (6, 3, 1, 1))
      self.assertTrue(f[1].shape == (6,))
  
imports: from torch import nn
  import unittest
  from towhee.models.utils.fuse_bn import fuse_bn
label_desc: Use image node_id 2 for calling the FuseBNTest obj's underlying member method code with example usage: obj.test_double() without return types