update learning_rate.py

ppcls/optimizer/learning_rate.py

@@ -14,7 +14,7 @@
 
 from __future__ import (absolute_import, division, print_function,
                         unicode_literals)
-
+import types
 from abc import abstractmethod
 from typing import Union
 
@@ -466,5 +466,12 @@ class ReduceOnPlateau(LRBase):
         if self.warmup_steps > 0:
             learning_rate = self.linear_warmup(learning_rate)
 
+        # NOTE: Implement get_lr() method for class `ReduceOnPlateau`,
+        # which is called in `log_info` function
+        def get_lr(self):
+            return self.last_lr
+
+        learning_rate.get_lr = types.MethodType(get_lr, learning_rate)
+
         setattr(learning_rate, "by_epoch", self.by_epoch)
         return learning_rate