code: def asn(self, ip, announce_date=None):
          
          assignations, announce_date, _ = self.run(ip, announce_date)
          return next((assign for assign in assignations if assign is not None), None), announce_date
docs: Give an IP, maybe a date, get the ASN.
              This is the fastest command.
  
              :param ip: IP address to search for
              :param announce_date: Date of the announcement
  
              :rtype: String, ASN.