code: def test_default_sizes(self):
      mha = attention.MultiHeadAttention(
          key_size=3, num_heads=5, w_init_scale=1.0
      )
      self.assertEqual(mha.value_size, mha.key_size)
      self.assertEqual(mha.model_size, mha.key_size * mha.num_heads)
  
file_path: dm-haiku/haiku/_src/attention_test.py
imports: from absl.testing import absltest
  from absl.testing import parameterized
  from haiku._src import attention
  from haiku._src import initializers
  from haiku._src import test_utils
  from haiku._src import transform
  import jax
  import jax.numpy
label_desc: Use image node_id 5 for calling the MultiHeadAttentionTest obj's underlying member method code with example usage: obj.test_default_sizes() without return types