code: def test_multihead_attn_no_bias(self):
      embed_dim = 8
      num_heads = 4
      mha = torch.nn.MultiheadAttention(
          embed_dim, num_heads, bias=False
      )
  
      # Verify that bias=False applies to both in and out projection layers.
      self.assertIsNone(mha.in_proj_bias)
      self.assertIsNone(mha.out_proj.bias)
  
imports: import contextlib
  import random
  import unittest
  import unittest.mock
  from torch.nn import MultiheadAttention
  from torch.testing._internal.common_device_type import instantiate_device_type_tests, dtypes, onlyCUDAAndPRIVATEUSE1
  from torch.testing._internal.common_nn import NNTestCase
  from torch.testing._internal.common_utils import run_tests, TEST_NUMPY, TEST_WITH_CROSSREF, parametrize, instantiate_parametrized_tests
  import torch.nn
  import torch
label_desc: Use image node_id 3 for calling the TestMultiheadAttentionNN obj's underlying member method code with example usage: obj.test_multihead_attn_no_bias() without return types