Use getFromKeyFields instead of getForFields where possible
Lookup by key_name is a lot faster than doing a query, so if possible
the use of getFromKeyFields is preferred over getForFields.
Patch by: Sverre Rabbelier
"""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