def append_dot(instring):
	""" Function returns a string with a single dot at the end, or an empty string if passed an empty object.
		This is usefull for building dot separated nodes from arbitrary strings that may already
		terminate with a dot, or be empty or None.
	"""
	if not instring:
		return ""	# return empty string if passed None
	if instring.endswith('.'):
		return instring
	return instring + '.'