diff --git a/tools/test.py b/tools/test.py
index 411f47fe4..f213b3794 100755
--- a/tools/test.py
+++ b/tools/test.py
@@ -122,7 +122,7 @@ def main():
             cfg.test_evaluator = list(cfg.test_evaluator)
             cfg.test_evaluator.append(dump_metric)
         elif isinstance(cfg.test_evaluator, dict):
-            if 'metrics' in cfg.test_evaluator.keys():
+            if 'metrics' in cfg.test_evaluator:
                 cfg.test_evaluator['metrics'].append(dump_metric)
             else:
                 cfg.test_evaluator['metrics'] = [dump_metric]