code: def _get_mx_exchanges(domain):
      
      try:
          answer = resolver.query(domain, 'MX')
          return [str(record.exchange).lower()[:-1] for record in answer]
      except (resolver.NoAnswer, resolver.NoNameservers, resolver.NotAbsolute,
              resolver.NoRootSOA, resolver.NXDOMAIN, resolver.Timeout) as error:
          LOGGER.error('Error querying MX for %s: %r', domain, error)
          return []
docs: Fetch the MX records for the specified domain
  
      :param str domain: The domain to get the MX records for
      :rtype: list