diff --git a/lib/sqlalchemy/util/langhelpers.py b/lib/sqlalchemy/util/langhelpers.py
index c97fa7d..9a02e7d 100644
--- a/lib/sqlalchemy/util/langhelpers.py
+++ b/lib/sqlalchemy/util/langhelpers.py
@@ -1657,6 +1657,8 @@
         items: List[symbol]
         cls._items = items = []
         for k, v in dict_.items():
+            if re.match(r"^__.*__$", k):
+                continue
             if isinstance(v, int):
                 sym = symbol(k, canonical=v)
             elif not k.startswith("_"):