code: def percent_bandwidth(data, period, std=2.0):
      
      catch_errors.check_for_period_error(data, period)
  
      period = int(period)
      percent_bandwidth = ((np.array(data) -
                           lower_bollinger_band(data, period, std)) /
                           bb_range(data, period, std)
                           )
  
      return percent_bandwidth
docs: Percent Bandwidth.
  
      Formula:
      %_bw = data() - l_bb() / bb_range()