code optimized

python/paddle/fluid/trainer.py

@@ -141,11 +141,7 @@ class Trainer(object):
         self.chief = True
         self.checkpoint = checkpoint_config
         if self.checkpoint:
-            if not isinstance(self.checkpoint, CheckpointConfig):
-                raise TypeError(
-                    "The checkpoint_config shoule be an instance of CheckpointConfig"
-                )
-            else:
+            assert isinstance(self.checkpoint, CheckpointConfig)
             serial = io.get_latest_checkpoint_serial(
                 self.checkpoint.checkpoint_dir)
             self.checkpoint.load_serial = serial if serial >= 0 else None
@@ -385,8 +381,8 @@ class Trainer(object):
                 else:
                     metrics = exe.run(feed=data, fetch_list=[])
 
-                event_handler(EndStepEvent(epoch_id, step_id, metrics))
                 self._save_checkpoint(epoch_id, step_id)
+                event_handler(EndStepEvent(epoch_id, step_id, metrics))
             event_handler(EndEpochEvent(epoch_id))
         self._clean_checkpoint()