Apply suggestions from code review

Mark-Yeatman · bnavigator · web-flow · commit 0ecc1354765c · 2022-06-07T11:49:47.000-04:00
Co-authored-by: Ben Greiner &lt;code@bnavigator.de&gt;
diff --git a/.github/workflows/python-package-conda.yml b/.github/workflows/python-package-conda.yml
@@ -13,7 +13,7 @@ jobs:
         python-version: [3.7, 3.9]
         slycot: ["", "conda"]
         pandas: [""]
-        cvxopt: ["conda"]
+        cvxopt: ["", "conda"]
         array-and-matrix: [0]
         include:
           - python-version: 3.9
diff --git a/control/exception.py b/control/exception.py
@@ -95,4 +95,4 @@ def cvxopt_check():
             cvxopt_installed = True
         except:
             cvxopt_installed = False
-    return cvxopt_installed
+    return cvxopt_installed
diff --git a/control/tests/passivity_test.py b/control/tests/passivity_test.py
@@ -5,7 +5,6 @@
 
 import numpy
 from control import ss, passivity
-from sympy import Matrix
 from control.tests.conftest import cvxoptonly
 
 @cvxoptonly
