code: def test_Mutan(self):
      fusion = fusions.Mutan(
          self.input_dims, self.output_dims, mm_dim=20
      )
      out = fusion(self.x)
      if torch.cuda.is_available():
          fusion.cuda()
          out = fusion([self.x[0].cuda(), self.x[1].cuda()])
      assert torch.Size([2, 2]) == out.shape
  
file_path: mmf/tests/modules/test_fusions.py
imports: import unittest
  import mmf.modules.fusions
  import torch
label_desc: Use image node_id 4 for calling the TestModuleFusions obj's underlying member method code with example usage: obj.test_Mutan() without return types