code: def _get_1f_sum_scans(self,d,freq):
          
          
          # combine scans: values with same frequency 
          unique_freq = np.unique(freq)
          
          sum_scans = [[] for i in range(len(d))]
          
          for f in unique_freq: 
              tag = freq==f
              for i in range(len(d)):
                  sum_scans[i].append(np.sum(d[i][tag]))
              
          return (np.array(unique_freq),np.array(sum_scans))
docs: Sum counts in each frequency bin over 1f scans.