- fix set syntax supposed to be dict

diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index 9a43c404d5070ee5e8822696131d981e3e9d4d46..ce48d4c4b44eb81b8cd79176dc627d06c9404075 100644 (file)
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -741,7 +741,7 @@ class Join(FromClause):
                 dedupe = set(tuple(crit) for crit in constraints.values())
                 if len(dedupe) == 1:
                     key = constraints.keys()[0]
-                    constraints = {key, constraints[key]}
+                    constraints = {key: constraints[key]}
 
             if len(constraints) != 1:
                 raise exc.AmbiguousForeignKeysError(