Returns an array of the dictionary’s keys, in the order they would be in if the dictionary were sorted by its values.
Original signature is '- (NSArray *)keysSortedByValueUsingSelector:(SEL)comparator'
Available in Mac OS X v10.0 and later.


- comparator (IntPtr)
- A selector that specifies the method to use to compare the values in the dictionary.

An array of the dictionary’s keys, in the order they would be in if the dictionary were sorted by its values.

- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)