def getFilterDomain(request):
	"""
	Return: {string} 'domain' param value based on hierarchy: URL param value -> session (last used) -> none.
	"""
	filterVal = request.GET.get('domain', None)
	filterByLastUsed = request.session.get('filterDomain', 'alldomains')
	if not filterVal and filterByLastUsed:
		filterVal = filterByLastUsed

	return filterVal