code: def _require_backsearch(self):
          
          if self.peak_num == self.n_peaks_i-1:
              # If we just return false, we may miss a chance to backsearch.
              # Update this?
              return False
  
          next_peak_ind = self.peak_inds_i[self.peak_num + 1]
  
          if next_peak_ind-self.last_qrs_ind > self.rr_recent*1.66:
              return True
          else:
              return False
docs: Determine whether a backsearch should be performed on prior peaks