diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index df10d33e..ab505f73 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -656,8 +656,7 @@ class ReferenceField(BaseField):
       * NULLIFY     - Updates the reference to null.
       * CASCADE     - Deletes the documents associated with the reference.
       * DENY        - Prevent the deletion of the reference object.
-      * PULL        - Pull the reference from a :class:`~mongoengine.ListField`
-                      of references
+      * PULL        - Pull the reference from a :class:`~mongoengine.ListField` of references
 
     Alternative syntax for registering delete rules (useful when implementing
     bi-directional delete rules)