':param id: Zone id.
:type id: ``str``
:param domain: The name of the domain.
:type domain: ``str``
:param type: Zone type (master, slave).
:type type: ``str``
:param ttl: Default TTL for records in this zone (in seconds).
:type ttl: ``int``
:param driver: DNSDriver instance.
:type driver: :class:`DNSDriver`
:param extra: (optional) Extra attributes (driver specific).
:type extra: ``dict``'

def __init__(self, id, domain, type, ttl, driver, extra=None):

    self.id = (str(id) if id else None)
    self.domain = domain
    self.type = type
    self.ttl = (ttl or None)
    self.driver = driver
    self.extra = (extra or {})
