Adjustment parameters in rdp.get_historical_price_events function

rdp.get_historical_price_events(
universe = 'AAPL.O',
start = datetime.timedelta(-1),
end = datetime.timedelta(0),
adjustments = [
rdp.Adjustments.EXCHANGE_CORRECTION,
rdp.Adjustments.MANUAL_CORRECTION
]
)

May I know what does the rdp.Adjustments.EXCHANGE_CORRECTION, and rdp.Adjustments.MANUAL_CORRECTION mean here