I have a piece of code that I don't understand. Can you answer it? Thank you!

[Ning-Wang]

//deprecated
SEL deprecatedSelector = NSSelectorFromString(@"codableKeys");
if ([self respondsToSelector:deprecatedSelector] || [self instancesRespondToSelector:deprecatedSelector])
{
NSLog(@"AutoCoding Warning: codableKeys method is no longer supported. Use codableProperties instead.");
}
deprecatedSelector = NSSelectorFromString(@"uncodableKeys");
if ([self respondsToSelector:deprecatedSelector] || [self instancesRespondToSelector:deprecatedSelector])
{
NSLog(@"AutoCoding Warning: uncodableKeys method is no longer supported. Use ivars, or synthesize your properties using non-KVC-compliant names to avoid coding them instead.");
}
deprecatedSelector = NSSelectorFromString(@"uncodableProperties");

codableKeys uncodableKeys uncodableProperties Where do these methods come from? Why do like This？
Thank you