Expected an indented block

[Nicoles07]

Hello I keep getting an error saying

Expected an indented block

but then i add an indentation and i get

inconsistent use of tabs and spaces

below is my code

class myHTTPTransport(HTTPTransport):
	username = None
	passwd = None

	@classmethod
	def setAuthentication(cls,u,p):
		cls.username = u
		cls.passwd = p

	def call(self, addr, data, namespace, soapaction=None, encoding=None,
		http_proxy=None, config=Config, timeout=None):

	if not isinstance(addr, SOAPAddress):
		addr=SOAPAddress(addr, config)

	if self.username != None:
		addr.user = self.username+":"+self.passwd

	return HTTPTransport.call(self, addr, data, namespace, soapaction,
								encoding, http_proxy, config)

thanks in advance