class_docstr: Base wrapper class.
class_docstr_tok: ["Base","wrapper","class","."]
docstr: Applies a wrapper-specific transformation to the history observations.
  
  Overridden in wrappers that alter observations.
  
  Args:
    frames: A tensor of history frames to transform.
  
  Returns:
    a tensor of transformed frames.
docstr_tok: ["Applies","a","wrapper-specific","transformation","to","the","history","observations",".","Overridden","in","wrappers","that","alter","observations",".","Args",":","frames",":","A","tensor","of","history","frames","to","transform",".","Returns",":","a","tensor","of","transformed","frames","."]
code: def _transform_history_observations(self, frames):
      """Applies a wrapper-specific transformation to the history observations.
  
      Overridden in wrappers that alter observations.
  
      Args:
        frames: A tensor of history frames to transform.
  
      Returns:
        a tensor of transformed frames.
      """
      return frames
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from six.moves import range
  from tensor2tensor.rl.envs.in_graph_batch_env import InGraphBatchEnv
  import tensorflow.compat.v1
label_desc: Use image node_id 7 for calling the WrapperBase obj's underlying member method code with example usage: obj._transform_history_observations(frames) and returns: frames