code: def _transpose_batch_time(tensor):
      """Transposes the batch and time dimension of tensor if its rank is at
      least 2."""
      shape = tensor.shape
      if shape.rank is not None and shape.rank < 2:
          return tensor
      perm = tf.concat(([1, 0], tf.range(2, tf.rank(tensor))), axis=0)
      return tf.transpose(tensor, perm)
  
imports: import abc
  import tensorflow
  from tensorflow_addons.utils.types import TensorLike
  from typeguard import typechecked
  from typing import Any, Optional, Tuple, Union
  from tensorflow.python.ops import control_flow_util
label_desc: Use image node_id 3 for calling a global function with example usage: _transpose_batch_time(tensor) and returns: tf, tensor