GetAvailability() returns the availability for a unit and date range. Availability is defined as a unit having not being rented, occupied or under repair and that is ready to be rented to guests. The start_date, end_date and the dates in between are dates of stay, not the check_in and check_out dates of a possible itinerary. Use GetQuote() to get availability for an itinerary.
Note: Once the advertiser has organized the units into unit_groups, units will no longer be accessible.