class_docstr: MKL Backend
class_docstr_tok: ["MKL","Backend"]
code: def bprop_mergesum(self, ngLayer, alpha, beta, layers, error, deltas):
      for i, l in enumerate(reversed(layers)):
          e = l.bprop(error)
          ngLayer.tensors[(i * 4) : (i * 4 + 4)] = e.primitive[0:4]
      self.sum_tensor(
          ngLayer.sum_prim_b,
          ngLayer.layer_num,
          ngLayer.tensors,
          deltas,
          ngLayer.shape5D,
      )
      deltas.shape5D = ngLayer.shape5D
  
imports: from __future__ import division
  from builtins import zip
  import logging
  from neon.backends import layer_mkl
  from neon.backends.util.check_mkl import get_mkl_lib
  from neon.backends.nervanacpu import CPUTensor, NervanaCPU, CustomNumpy
  import ctypes
  from cffi import FFI
  from ctypes import c_longlong, c_float, c_double, c_int
  import numpy
  from neon.backends import math_cpu
  from neon.backends.backend import OpTreeNode
  import os
  import sys
label_desc: Use image node_id 29 for calling the NervanaMKL obj's underlying member method code with example usage: obj.bprop_mergesum(ngLayer, alpha, beta, layers, error, deltas) without return types