Update ref-metrics.py

ref-metrics.py

@@ -129,7 +129,7 @@ class UserFriendlyMetrics(evaluate.Metric):
 
     def dummy_values(self, area_ranges_tuples=None):
         """Dummy randome values in the expected format that all new metrics need to return"""
-
+        ---
         # Use default ranges if none are provided
         if area_ranges_tuples is None:
             area_names = ["all", "small", "medium", "large"]