docstr: get a custom layer maker provided by subclass
          
docstr_tok: ["get","a","custom","layer","maker","provided","by","subclass"]
code: def custom_layer_factory(self):
      """get a custom layer maker provided by subclass"""
      raise NotImplementedError(
          "[custom_layer_factory] must be implemented by the subclass."
      )
  
imports: from __future__ import print_function
  from builtins import str
  from past.builtins import basestring
  from builtins import object
  import sys
  import os
  import math
  import numpy
label_desc: Use image node_id 27 for calling the Network obj's underlying member method code with example usage: obj.custom_layer_factory() without return types