class test(object):
	_informations = {'a':'test'}
	def __getattr__(self, name):
		if "name" in self._informations:
			return self._informations[name]
		else:
			# WHAT HAVE I GOT TO WRITE HERE?


t = test()
print t.a # should be result in output 'test'
print t   # results in 'NoneType' Exception when else part is missing