fix ema_filter_no_grad (#7974)

ppdet/optimizer/ema.py

@@ -60,6 +60,12 @@ class ModelEMA(object):
         self.cycle_epoch = cycle_epoch
         self.ema_black_list = self._match_ema_black_list(
             model.state_dict().keys(), ema_black_list)
+        bn_states_names = get_bn_running_state_names(model)
+        if ema_filter_no_grad:
+            for n, p in model.named_parameters():
+                if p.stop_gradient and n not in bn_states_names:
+                    self.ema_black_list.add(n)
+
         self.state_dict = dict()
         for k, v in model.state_dict().items():
             if k in self.ema_black_list:
@@ -67,12 +73,6 @@ class ModelEMA(object):
             else:
                 self.state_dict[k] = paddle.zeros_like(v)
 
-        bn_states_names = get_bn_running_state_names(model)
-        if ema_filter_no_grad:
-            for n, p in model.named_parameters():
-                if p.stop_gradient == True and n not in bn_states_names:
-                    self.ema_black_list.append(n)
-
         self._model_state = {
             k: weakref.ref(p)
             for k, p in model.state_dict().items()