Compose permission name

        @param resource the resource
        @param method the request method (case doesn't matter).

def get_perm_name(cls, resource, method):
        """ Compose permission name

        @param resource the resource
        @param method the request method (case doesn't matter).
        """

        return '%s_%s_%s' % (
            cls.PREFIX,
            cls._get_resource_name(resource),
            method.lower())