'Ensure session user has authorized silent OpenID login.
If no user is logged in or has not authorized silent login, this
method should return False.
If the user is logged in but associated with multiple accounts and
not selected which one to link to the token then this method should
raise an oauthlib.oauth2.AccountSelectionRequired error.
:param request: The HTTP Request (oauthlib.common.Request)
:rtype: True or False
Method is used by:
- OpenIDConnectAuthCode
- OpenIDConnectImplicit
- OpenIDConnectHybrid'

def validate_silent_login(self, request):

    raise NotImplementedError(u'Subclasses    must    implement    this    method.')
