code: def check_dns_cname(domain, prefix, code):
      
      fqdn = '{}-{}.{}'.format(prefix, code, domain)
      try:
          for rr in dns.resolver.query(fqdn, 'CNAME'):
              if rr.to_text().startswith(prefix + '.'):
                  return True
      except:
          logger.debug('', exc_info=True)
      return False
docs: Validates a domain by checking the existance of the CNAME record on the domain as:
      {prefix}-{code}.{domain} pointing to a domain (usually yours) which the host is {prefix}
      (i.e.: {prefix}.yourdomain.com).
  
      Returns true if verification suceeded.