@@ -14,10 +14,12 @@
  * file.
  */
 
 #import "OFObject.h"
 
+OF_ASSUME_NONNULL_BEGIN
+
 @class OFString;
 
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -32,5 +34,7 @@
  *
  * @return The object serialized as a string
  */
 - (OFString*)stringBySerializing;
 @end
+
+OF_ASSUME_NONNULL_END