diff --git a/arthur/arthur.py b/arthur/arthur.py
index 3279ffd..09ba3c5 100644
--- a/arthur/arthur.py
+++ b/arthur/arthur.py
@@ -95,7 +95,7 @@ def remove_task(self, task_id):
         """
         try:
             self._scheduler.cancel_task(task_id)
-        except NotFoundError as e:
+        except NotFoundError:
             logger.info("Cannot cancel %s task because it does not exist.",
                         task_id)
             return False
diff --git a/tests/test_arthur.py b/tests/test_arthur.py
index d20b24e..975bb1b 100644
--- a/tests/test_arthur.py
+++ b/tests/test_arthur.py
@@ -288,7 +288,7 @@ def test_task_wrong_delay(self):
 
         app = Arthur(self.conn, async_mode=False)
 
-        with self.assertRaisesRegex(ValueError, INVALID_SCHEDULER_DELAY) as ex:
+        with self.assertRaisesRegex(ValueError, INVALID_SCHEDULER_DELAY):
             app.add_task(task_id, backend, category, backend_params, sched_args=sched_params)
 
     def test_task_wrong_max_retries(self):
@@ -302,7 +302,7 @@ def test_task_wrong_max_retries(self):
 
         app = Arthur(self.conn, async_mode=False)
 
-        with self.assertRaisesRegex(ValueError, INVALID_SCHEDULER_MAX_RETRIES) as ex:
+        with self.assertRaisesRegex(ValueError, INVALID_SCHEDULER_MAX_RETRIES):
             app.add_task(task_id, backend, category, backend_params, sched_args=sched_params)
 
     def test_add_duplicated_task(self):