Do not rely on notifiction module being imported
This has worked so far mostly by accident, but it turned out to be
brittle while writing tests. This makes sure that the notification
module is always imported before use.
"""Multi-consumer multi-producer dispatching mechanism
Originally based on pydispatch (BSD) http://pypi.python.org/pypi/PyDispatcher/2.0.1
See license.txt for original license.
Heavily modified for Django's purposes.
"""
from django.dispatch.dispatcher import Signal