diff --git a/tidbcloudy/api/_base.py b/tidbcloudy/api/_base.py
index b9a4cab..4ed5de1 100644
--- a/tidbcloudy/api/_base.py
+++ b/tidbcloudy/api/_base.py
@@ -22,7 +22,8 @@ class TiDBCloudyBase:
     def __init_subclass__(cls):
         cls._keys = {}
         for key in cls.__slots__:
-            key = key.removeprefix("_")
+            if key.startswith("_"):
+                key = key[1:]
             cls._keys[key] = getattr(cls, key)
 
     def __init__(self, **kwargs):