Getting info on private Cocoa frameworks

class-dump is a great tool for getting information about how private frameworks work that you may want to use. For example, iPhotoAccess.framework gave among other classes the following:
`
@interface Base64 : NSObject
{
}

+ (id)stringForBase64:(id)fp8;

• (id)base64ForString:(id)fp8;

  @end
  `