code: def __normalise(self, img_data, mask, mapping):
      return hs.transform_by_mapping(
          img_data, mask, mapping, self.cutoff, self.norm_type
      )
  
file_path: NiftyNet/niftynet/layer/histogram_normalisation.py
imports: from __future__ import absolute_import, print_function, division
  import os
  import numpy
  import tensorflow
  import niftynet.utilities.histogram_standardisation
  from niftynet.layer.base_layer import DataDependentLayer
  from niftynet.layer.binary_masking import BinaryMaskingLayer
label_desc: Use image node_id 7 for calling the HistogramNormalisationLayer obj's underlying member method code with example usage: obj.__normalise(img_data, mask, mapping) and returns: hs