[commands/cache] fix linting error.
@@ -75,7 +75,7 @@ def test_cache_remove(script, monkeypatch):
def test_cache_remove_too_many_args(script, monkeypatch):
- result = script.pip('cache', 'remove', 'aaa', 'bbb',
+ script.pip('cache', 'remove', 'aaa', 'bbb',
expect_error=True)
