code: def bb_range(data, period, std=2.0):
      
      catch_errors.check_for_period_error(data, period)
  
      period = int(period)
      bb_range = (upper_bollinger_band(data, period, std) -
                  lower_bollinger_band(data, period, std)
                  )
      return bb_range
docs: Range.
  
      Formula:
      bb_range = u_bb - l_bb