code: def test_mha_with_lrp(self):
      seq_len = 21
      c_dim = 10
      mod = MultiHeadAttention(c_dim, num_heads=2)
      fake_input = torch.rand(8, seq_len, c_dim)
      out1 = mod(fake_input)
      kwargs = {"alpha": 1}
      # torch.Size([8, 21, 10])
      out2 = mod.relprop(out1, **kwargs)
      self.assertTrue(out2.shape == torch.Size([8, 21, 10]))
  
imports: import unittest
  import torch
  from towhee.models.layers.attention import MultiHeadAttention, Attention
label_desc: Use image node_id 1 for calling the AttentionTest obj's underlying member method code with example usage: obj.test_mha_with_lrp() without return types