diff --git a/wecopttool/pto.py b/wecopttool/pto.py
index 71996b21..e34b3b1e 100644
--- a/wecopttool/pto.py
+++ b/wecopttool/pto.py
@@ -1074,7 +1074,7 @@ def controller_p(
     """
     force_td = controller_pid(
         pto, wec, x_wec, x_opt, waves, nsubsteps,
-        True, False, False, saturation
+        True, False, False, saturation,
     )
     return force_td