code: def is_recurrent(layer):
      """Return True iff a given layer is recurrent and supported by PFRL.
  
      Args:
          layer (callable): Any callable object.
  
      Returns:
          bool: True iff a given layer is recurrent and supported by PFRL.
      """
      # Import here to avoid circular import
      from pfrl.nn import Recurrent
  
      return isinstance(
          layer,
          (
              nn.LSTM,
              nn.RNN,
              nn.GRU,
              Recurrent,
          ),
      )
  
file_path: pfrl/pfrl/utils/recurrent.py
imports: import itertools
  import numpy
  import torch
  from torch import nn
label_desc: Use image node_id 1 for calling a global function with example usage: is_recurrent(layer) and returns: isinstance