def _hostname(self, fqdn):
        zone = '.' + self.zone
        assert fqdn.endswith(zone)
        return fqdn[:-len(zone)]
Asserts that the given FQDN belong to the configured zone and
dataset/ETHPy150Open marccerrato/python-dns-failover/dns_failover/backends.py/CloudFlareDNS._hostname