code: def get_freq_map_and_normalizations(self, frequency_list,
                                          upper_freq_formula):
          
          self.frequency_map = {}
          self.normalization_map = {}
          self.upper_freq_formula = upper_freq_formula
          # FIXME: Must this be sorted on input
          frequency_list.sort()
  
          for idx, frequency in enumerate(frequency_list):
              self.frequency_map[frequency] = idx
              self.normalization_map[frequency] = \
                               (self.metric_params.moments['I7'][frequency])**0.5
docs: If using the --vary-fupper capability we need to store the mapping
          between index and frequencies in the list. We also precalculate the
          normalization factor at every frequency, which is used when estimating
          overlaps to account for abrupt changes in termination frequency.
  
          Parameters
          -----------
          frequency_list : array of floats
              The frequencies for which the metric has been computed and lie
              within the parameter space being considered.
          upper_freq_formula : string