fix turtle import bug

ppcls/engine/train/train_fixmatch_ccssl.py

 from __future__ import absolute_import, division, print_function
 import time
-from turtle import update
 import paddle
 from ppcls.engine.train.train_fixmatch import get_loss
 from ppcls.engine.train.utils import update_loss, update_metric, log_info
@@ -123,4 +122,4 @@ def get_loss(engine,
             loss_dict[k] = v
     loss_dict['loss'] = loss_dict_label['loss'] + unlabel_loss['loss']
 
-    return loss_dict, logits_x
\ No newline at end of file
+    return loss_dict, logits_x