class_docstr: A simple out-of-graph Replay Buffer.
  
  Stores transitions, state, action, reward, next_state, terminal (and any
  extra contents specified) in a circular buffer and provides a uniform
  transition sampling function.
  
  When the states consist of stacks of observations storing the states is
  inefficient. This class writes observations and constructs the stacked states
  at sample time.
  
  Attributes:
    add_count: int, counter of how many transitions have been added (including
      the blank ones at the beginning of an episode).
    invalid_range: np.array, an array with the indices of cursor-related invalid
      transitions
    episode_end_indices: set[int], a set of indices corresponding to the
      end of an episode.
docstr: The signature of the add function.
  
  Note - Derived classes may return a different signature.
  
  Returns:
    list of ReplayElements defining the type of the argument signature needed
      by the add function.
docstr_tok: ["The","signature","of","the","add","function",".","Note","-","Derived","classes","may","return","a","different","signature",".","Returns",":","list","of","ReplayElements","defining","the","type","of","the","argument","signature","needed","by","the","add","function","."]
code: def get_add_args_signature(self):
      """The signature of the add function.
  
      Note - Derived classes may return a different signature.
  
      Returns:
        list of ReplayElements defining the type of the argument signature needed
          by the add function.
      """
      return self.get_storage_signature()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import gzip
  import math
  import os
  import pickle
  from absl import logging
  import gin.tf
  import numpy
  import tensorflow
label_desc: Use image node_id 4 for calling the OutOfGraphReplayBuffer obj's underlying member method code with example usage: obj.get_add_args_signature() and returns: self