diff --git a/rigify/rot_mode.py b/rigify/rot_mode.py
index fbc425f6b9145bd702bba5b6be7e6b49be217941..50e7987738c7cad9329e699954613b00d6299c7e 100644
--- a/rigify/rot_mode.py
+++ b/rigify/rot_mode.py
@@ -50,7 +50,7 @@ class convert():
             if fc.data_path == data_path and (array_index < 0 or fc.array_index == array_index):
                 return fc
 
-        fc = action.fcurves.new(data_path, array_index)
+        fc = action.fcurves.new(data_path, index=array_index)
         fc.group = group
         return fc