fix: lint issues with test_asyncio_wait.py

Author: smoke

instrumentation/opentelemetry-instrumentation-asyncio/tests/test_asyncio_wait.py

@@ -69,17 +69,17 @@ async def main():
         self.assertEqual(len(spans), 2)
 
     def test_asyncio_wait_for_with_timeout(self):
-        ex = None
+        expected_timeout_error = None
 
         async def main():
-            nonlocal ex
+            nonlocal expected_timeout_error
             try:
                 await asyncio.wait_for(async_func(), 0.01)
-            except asyncio.TimeoutError as e:
-                ex = e
+            except asyncio.TimeoutError as timeout_error:
+                expected_timeout_error = timeout_error
 
         asyncio.run(main())
-        self.assertNotEqual(ex, None)
+        self.assertNotEqual(expected_timeout_error, None)
 
     def test_asyncio_as_completed(self):
         async def main():