[Bugfix] issue PharMolix#12 (PharMolix#13)

Co-authored-by: BioFM <[email protected]>

open_biomed/utils/utils.py

@@ -145,7 +145,7 @@ def _check_lower(self, score, prev_best_score):
         """
         return score < prev_best_score
 
-    def step(self, score, model, epoch):
+    def step(self, score, model, epoch=-1):
         """Update based on a new score.
         The new score is typically model performance on the validation set
         for a new epoch.