code: def _timebin_self_attention_fn(self, use_reference_code=False):
      return functools.partial(
          tl.SelfAttention,
          attention_dropout=0.05,
          chunk_len=64,
          n_chunks_before=1,
          n_parallel_heads=1,
          use_reference_code=use_reference_code,
      )
  
imports: import functools
  from absl.testing import absltest
  from absl.testing import parameterized
  import gin
  import numpy
  from trax import fastmath
  from trax import layers
  from trax import shapes
  from trax.layers import test_utils
  from trax.models.research import terraformer
label_desc: Use image node_id 3 for calling the TerraformerTest obj's underlying member method code with example usage: obj._timebin_self_attention_fn(use_reference_code) and returns: functools