'Get the status string of the first authorization for the given domain.
Return None if no active authorization for the given domain was found.'

def _get_domain_auth(self, domain):

    if (self.authorizations is None):
        return None
    for auth in self.authorizations:
        if ((auth['identifier']['type'] == 'dns') and (auth['identifier']['value'] == domain)):
            return auth
    return None
