code: def backward(self, state, root_gradients):
      input = state
      grad = np.abs(input)
      grad = np.less_equal(grad, 1)
      return grad * root_gradients
  
imports: from cntk import *
  from cntk.ops.functions import UserFunction
  import numpy
  import cntk
label_desc: Use image node_id 3 for calling the pySign obj's underlying member method code with example usage: obj.backward(state, root_gradients) and returns: unknown