@@ -16,11 +16,11 @@
 
 #import <Foundation/NSString.h>
 
 #import "NSBridging.h"
 
-NS_ASSUME_NONNULL_BEGIN
+OF_ASSUME_NONNULL_BEGIN
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 extern int _NSString_OFObject_reference;
@@ -39,6 +39,6 @@
  * character of OFString is 4).
  */
 @interface NSString (OFObject) <NSBridging>
 @end
 
-NS_ASSUME_NONNULL_END
+OF_ASSUME_NONNULL_END