Wierd SQL Alchemy Error

Code that Creates it

  def catalogs_home(request):
      userid = authenticated_userid(request)
      username = Users.by_id(userid).username
      clients = DBSession.query(Clients).order_by(Clients.active).all()
      commodities_count = []
      sandbox_status = []
      production_status = []
      for client in clients:
          category_count = 0 
          for category in client.categories:
              category_count += DBSession.query(Commodities).filter(Commodities.category_id == category.category_id).co
          commodities_count.append(category_count)
  
          sandbox_cat, sandbox_com = verify_catalog_publishing(client.client_id, False)
          if not sandbox_cat.find('COMPLETE') and not sandbox_com.find('COMPLETE'):
              sandbox_status.append('In Progress')
          production_cat, production_com = verify_catalog_publishing(client.client_id, True)
          if not production_cat.find('COMPLETE') and not production_com.find('COMPLETE'):
              production_status.append('In Progress')

Error

DetachedInstanceError: Parent instance <Clients at 0x108317f10> is not bound to a Session; lazy load operation of attribute 'categories' cannot proceed

If I comment out lines 14-19 below I do not get the error.


Traceback (most recent call last):
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid_debugtoolbar-1.0.4-py2.7.egg/pyramid_debugtoolbar/panels/performance.py", line 55, in resource_timer_handler
    result = handler(request)
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid/tweens.py", line 21, in excview_tween
    response = handler(request)
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid_tm-0.7-py2.7.egg/pyramid_tm/__init__.py", line 82, in tm_tween
    reraise(*exc_info)
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid_tm-0.7-py2.7.egg/pyramid_tm/__init__.py", line 63, in tm_tween
    response = handler(request)
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid/router.py", line 161, in handle_request
    response = view_callable(context, request)
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid/config/views.py", line 237, in _secured_view
    return view(context, request)
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid/config/views.py", line 345, in rendered_view
    result = view(context, request)
  File "/Users/jasonamyers/.virtualenv/cornerstone/lib/python2.7/site-packages/pyramid/config/views.py", line 491, in _requestonly_view
    response = view(request)
  File "/Users/jasonamyers/projects/cornerstone/cornerstone/views/catalogs.py", line 35, in catalogs_home
    for category in client.categories:
  File "build/bdist.macosx-10.8-x86_64/egg/sqlalchemy/orm/attributes.py", line 251, in __get__
    return self.impl.get(instance_state(instance), dict_)
  File "build/bdist.macosx-10.8-x86_64/egg/sqlalchemy/orm/attributes.py", line 545, in get
    value = self.callable_(state, passive)
  File "build/bdist.macosx-10.8-x86_64/egg/sqlalchemy/orm/strategies.py", line 497, in _load_for_state
    (orm_util.state_str(state), self.key)
DetachedInstanceError: Parent instance <Clients at 0x108317f10> is not bound to a Session; lazy load operation of attribute 'categories' cannot proceed