@@ -249,15 +249,15 @@
 /*!
  * @brief Returns the next object.
  *
  * @return The next object
  */
-- (void *)nextObject;
+- (nullable void *)nextObject;
 
 /*!
  * @brief Resets the enumerator, so the next call to @ref nextKey returns the
  *	  first key again.
  */
 - (void)reset;
 @end
 
 OF_ASSUME_NONNULL_END