A class for support more than one authentication method configured at same time

I have tried to add support more than one authentication method configured at same time making a class that implements
XWikiAuthService. The class read the stackable.authclasses parameter (in xwiki.cfg) or stackable_authclasses property (in XWiki.XWikiPreferences). It must be set to a colon separated list of authentication service classes that will be tried in order during authentication.