def volume_oscillator(volume, short_period, long_period):
catch_errors.check_for_period_error(volume, short_period)<EOL>catch_errors.check_for_period_error(volume, long_period)<EOL>vo = (<NUM_LIT:100> * ((sma(volume, short_period) - sma(volume, long_period)) /<EOL>sma(volume, long_period)))<EOL>return vo<EOL>
Volume Oscillator.

Formula:
vo = 100 * (SMA(vol, short) - SMA(vol, long) / SMA(vol, long))