class_docstr: @note: Non-differentiable.
code: def perform(self, node, inp, out_):
      (x,) = inp
      (out,) = out_
      out[0] = x
  
imports: from __future__ import absolute_import, print_function, division
  import unittest
  from theano.tests import unittest_tools
  from theano import function
  import theano
  from theano import tensor
  import itertools
  import numpy
  from theano.gof import Op, Apply
  from theano.gradient import grad_undefined
  from theano.tests.unittest_tools import SkipTest
  from theano.tensor.signal.pool import Pool
  from theano.tensor.nnet import conv, conv2d
label_desc: Use image node_id 2 for calling the BreakRop obj's underlying member method code with example usage: obj.perform(node, inp, out_) without return types