Remove unused import.

Mark-Yeatman · web-flow · commit dc46f3cf2c70 · 2022-06-07T11:48:36.000-04:00
diff --git a/control/passivity.py b/control/passivity.py
@@ -3,7 +3,6 @@
 Date: May 15, 2022
 '''
 
-from . import statesp as ss
 import numpy as np
 import cvxopt as cvx
 
