text: #import <Foundation/Foundation.h>
  
  extern NSString* const SINServiceErrorDomain;
  
  typedef NS_ENUM(NSInteger, SINServiceError) {
    SINServiceErrorComponentNotAvailable = 1,
    SINServiceErrorUserIdNotAvailable
  };
  
  extern NSError* SINServiceComponentNotAvailableError();
  extern NSError* SINServiceCreateError(SINServiceError code, NSString* reason);
  