diff --git a/manimlib/mobject/mobject.py b/manimlib/mobject/mobject.py
index 8ef3625b..3e4d5f61 100644
--- a/manimlib/mobject/mobject.py
+++ b/manimlib/mobject/mobject.py
@@ -84,7 +84,7 @@ class Mobject(object):
 
     def __add__(self, other : 'Mobject') -> 'Mobject':
         assert(isinstance(other, Mobject))
-        return self.get_group_class(self, other)
+        return self.get_group_class()(self, other)
 
     def __mul__(self, other : 'int') -> 'Mobject':
         assert(isinstance(other, int))