Fixed SQL_IN when getquoted() is called without prepare()

lib/extensions.py

@@ -116,9 +116,9 @@ def register_adapter(typ, callable):
 # The SQL_IN class is the official adapter for tuples starting from 2.0.6.
 class SQL_IN(object):
     """Adapt any iterable to an SQL quotable object."""
-    
     def __init__(self, seq):
         self._seq = seq
+        self._conn = None
 
     def prepare(self, conn):
         self._conn = conn
@@ -127,6 +127,7 @@ class SQL_IN(object):
         # this is the important line: note how every object in the
         # list is adapted and then how getquoted() is called on it
         pobjs = [adapt(o) for o in self._seq]
+        if self._conn is not None:
             for obj in pobjs:
                 if hasattr(obj, 'prepare'):
                     obj.prepare(self._conn)