refactor: remove unused variable in pytest plugin

Removed the `add_markers` variable, as it was declared but never used.
This cleanup helps reduce code clutter and improves readability.

diff --git a/lib/sqlalchemy/testing/plugin/pytestplugin.py b/lib/sqlalchemy/testing/plugin/pytestplugin.py
index aa531776f805204ee8e6011890f6fd77ac196a21..79d14458ca89a52ad2bde0feeac95779eecb79e9 100644 (file)
--- a/lib/sqlalchemy/testing/plugin/pytestplugin.py
+++ b/lib/sqlalchemy/testing/plugin/pytestplugin.py
@@ -270,7 +270,6 @@ def pytest_collection_modifyitems(session, config, items):
         for test_class in test_classes:
             # transfer legacy __backend__ and __sparse_backend__ symbols
             # to be markers
-            add_markers = set()
             if getattr(test_class.cls, "__backend__", False) or getattr(
                 test_class.cls, "__only_on__", False
             ):