code: def volume_oscillator(volume, short_period, long_period):
      
      catch_errors.check_for_period_error(volume, short_period)
      catch_errors.check_for_period_error(volume, long_period)
  
      vo = (100 * ((sma(volume, short_period) - sma(volume, long_period)) /
            sma(volume, long_period)))
      return vo
docs: Volume Oscillator.
  
      Formula:
      vo = 100 * (SMA(vol, short) - SMA(vol, long) / SMA(vol, long))