code: def test_mb_conv(self):
      model = MBConv(in_channels=30, out_channels=30)
      x = torch.randn(1, 30, 28, 28)
      out = model(x)
      self.assertEqual(out.shape, (1, 30, 28, 28))
  
imports: import unittest
  import torch
  from towhee.models.layers.mbconv import MBConv
label_desc: Use image node_id 1 for calling the MbConvTest obj's underlying member method code with example usage: obj.test_mb_conv() without return types