'query method for Notifications list
:param view_kwargs:
:return:'

def query(self, view_kwargs):

    query_ = self.session.query(Notification)
    if view_kwargs.get('user_id'):
        user = safe_query(self, User, 'id', view_kwargs['user_id'], 'user_id')
        query_ = query_.join(User).filter((User.id == user.id))
    return query_
