code: def expand_batch_coordinates(bc, length_factor):
      """Duplicate elements of bc by length_factor.
  
      Args:
        bc (tf.Tensor): int32 tensor of shape [1, length, 1]
        length_factor (int):
  
      Returns:
        tf.Tensor: of shape [1, length*length_factor, 1] where every elements has
          been duplicated length_factor times.
      """
      assert bc.get_shape().as_list() == [1, None, 1]
      # bc has shape [1, length, 1]
      bc *= tf.constant([[1] * length_factor])
      # bc has shape [1, length, length_factor]
      bc = tf.reshape(bc, [1, -1, 1])
      # bc has shape [1, length*length_factor]
      return bc
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import functools
  from six.moves import range
  from tensor2tensor.layers import common_attention
  from tensor2tensor.layers import common_hparams
  from tensor2tensor.layers import common_layers
  from tensor2tensor.utils import expert_utils
  from tensor2tensor.utils import registry
  from tensor2tensor.utils import t2t_model
  import tensorflow.compat.v1
  from tensorflow.compat.v1 import estimator
label_desc: Use image node_id 3 for calling a global function with example usage: expand_batch_coordinates(bc, length_factor) and returns: bc