code: def forward(self, input):
      return input
  
imports: from collections.abc import Callable
  import numpy
  import paddle
  import paddle.nn
  from paddle.nn.initializer import TruncatedNormal, Constant, Normal
  from ppdet.core.workspace import register, serializable
label_desc: Use image node_id 2 for calling the Identity obj's underlying member method code with example usage: obj.forward(input) and returns: input