--- a/iro/model/utils.py	Thu Mar 29 16:27:40 2012 +0200
+++ b/iro/model/utils.py	Thu Mar 29 17:21:46 2012 +0200
@@ -1,15 +1,22 @@
 from sqlalchemy.orm import sessionmaker
 
 from .session import IroSession
+class WithSession(object):
+    '''a with statement for a database session connection.'''
+    def __init__(self, engine, autocommit=False):
+        """
+        :param `sqlalchemy.engine.base.Engine` engine: a valid sqlalchemy engine object (normally created via :func:`sqlalchemy.create_engine`).
+        :param boolean autocommit: autocommit after running the function.
 
-class WithSession(object):
-    '''a with statement for a database session connection'''
-    def __init__(self, engine, autocommit=False):
+        .. automethod:: __enter__
+        """
         self.engine = engine
         self.autocommit=autocommit
     
     def __enter__(self):
         self.session = sessionmaker(bind=self.engine, class_ = IroSession)()
+        """returns a vaild session object"""
+        self.session = sessionmaker(bind=self.engine)()
         return self.session
     
     def __exit__(self,exc_type, exc_value, traceback):