against is optional

diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index 5f17c223c5acf68f70063a7f8477f6d3a51ddd7a..a4504e83303f2ec09c9031de8304457558e28a81 100644 (file)
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -2598,7 +2598,7 @@ class _UnaryExpression(ColumnElement):
         else:
             return super(_UnaryExpression, self)._negate()
 
-    def self_group(self, against):
+    def self_group(self, against=None):
         if self.operator and operators.is_precedent(self.operator, against):
             return _Grouping(self)
         else: