diff --git a/tools/linter_lib/custom_check.py b/tools/linter_lib/custom_check.py
index 86e5a0e995..e512a870d5 100644
--- a/tools/linter_lib/custom_check.py
+++ b/tools/linter_lib/custom_check.py
@@ -191,9 +191,9 @@ def build_custom_checkers(by_lang):
     python_rules = cast(RuleList, [
         {'pattern': '^(?!#)@login_required',
          'description': '@login_required is unsupported; use @zulip_login_required'},
-        {'pattern': '".*"%\([a-z_].*\)?$',
+        {'pattern': '".*"%\(.*\)?$',
          'description': 'Missing space around "%"'},
-        {'pattern': "'.*'%\([a-z_].*\)?$",
+        {'pattern': "'.*'%\(.*\)?$",
          'exclude': set(['analytics/lib/counts.py',
                          'analytics/tests/test_counts.py',
                          ]),