refactoring code

main.py

@@ -121,6 +121,7 @@ def train(args, cfg):
         if best_val_loss != None:
             if val_loss < best_val_loss :
                 network_checkpoint.update(val_loss)
+                best_val_loss = val_loss
 
         scheduler.step(val_loss)
 
@@ -207,6 +208,6 @@ if __name__ == "__main__":
     
     config_file = open("config.yml")
     cfg = yaml.load(config_file, Loader=yaml.FullLoader)
-    
+
     eval(f"{args.command}(args)")