some cleanup

plugins/sa_plugin.py

@@ -7,9 +7,6 @@ from sqlalchemy.orm import scoped_session, sessionmaker
 
 __all__ = ['SAEnginePlugin']
 
-if sa_version.split('.') < ['0', '7', '4']:
-    raise ImportError('Version 0.7.4 or later of SQLAlchemy required.')
-
 class SAEnginePlugin(plugins.SimplePlugin):
     """
         SQLAlchemy integration for CherryPy

tools/sa_tool.py

@@ -10,11 +10,12 @@ class SATool(cherrypy.Tool):
     def __init__(self):
         super(SATool, self).__init__('on_start_resource', self.bind_session,
                                      priority=20)
+        self.session = None
 
     def _setup(self):
         super(SATool, self)._setup()
-        cherrypy.serving.request.hooks.attach('on_end_resource',
-                                              self.remove_session, priority=80)
+        cherrypy.request.hooks.attach('on_end_resource',
+                                      self.remove_session, priority=80)
 
     def bind_session(self):
         self.session = cherrypy.engine.publish('get-session').pop()