code: def _IsotonicRegressionGrad(
      op: ops.Operation, grad_output, grad_segments
  ):
      """Gradient for the isotonic regression function.
  
      Args:
        op: The IsotonicRegression tensorflow op.
        grad_output: Tensor of incoming gradients with respect to the output.
        grad_segments: Tensor of incoming gradients with respect to the segments.
  
      Returns:
        A tensor, same size as `grad_output` with the gradient with respect to
        the input.
      """
      del grad_segments  # Discrete, non-differentiable.
      segments = op.outputs[1]
      return _MeanAggregator(grad_output, segments)
  
imports: import functools
  import itertools
  import operator
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import array_ops_stack
  from tensorflow.python.ops import gen_nn_ops
  from tensorflow.python.ops import math_ops
label_desc: Use image node_id 60 for calling a global function with example usage: _IsotonicRegressionGrad(op, grad_output, grad_segments) and returns: _MeanAggregator