add early return if there are no timestrings in pred and ref

logscoremetric.py

@@ -108,9 +108,13 @@ class LogScoreMetric(evaluate.Metric):
         if(len(pred_timestrings) != len(ref_timestrings)):
             return 0.0
         
+        # If there are no timestrings, we must not check anything, we can directly return 1.0
+        if (len(pred_timestrings) == 0):
+            return 1.0
+        
         # replace all digits in the reference timestamp (first timestamp) with '/d' to get
         # a regex that describes the format  
-        pred_timestring_pattern = re.sub(r'\d', r'\\d', re.escape(pred_timestrings[0])) if (len(pred_timestrings) > 0) else ""
+        pred_timestring_pattern = re.sub(r'\d', r'\\d', re.escape(pred_timestrings[0]))
         
         # A variable to save the previous timestamp (as datetime obj) to check monotonicity
         prev_datetime = None