mypy: Enable new error explicit-override.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

analytics/management/commands/clear_single_stat.py

@@ -2,6 +2,7 @@ from argparse import ArgumentParser
 from typing import Any
 
 from django.core.management.base import BaseCommand, CommandError
+from typing_extensions import override
 
 from analytics.lib.counts import COUNT_STATS, do_drop_single_stat
 
@@ -9,10 +10,12 @@ from analytics.lib.counts import COUNT_STATS, do_drop_single_stat
 class Command(BaseCommand):
     help = """Clear analytics tables."""
 
+    @override
     def add_arguments(self, parser: ArgumentParser) -> None:
         parser.add_argument("--force", action="store_true", help="Actually do it.")
         parser.add_argument("--property", help="The property of the stat to be cleared.")
 
+    @override
     def handle(self, *args: Any, **options: Any) -> None:
         property = options["property"]
         if property not in COUNT_STATS: