'Links emails with a user ID and informs an identity server.
Used only by c/s api v1'

@defer.inlineCallbacks
def bind_emails(self, user_id, threepidCreds):

    for c in threepidCreds:
        identity_handler = self.hs.get_handlers().identity_handler
        (yield identity_handler.bind_threepid(c, user_id))
