code: def add_alias(self, alias):
          
          aliases = self.list_aliases()
          if alias in aliases:
              logger.debug("Alias %s already exists on %s.", alias, self.anonymize_url(self.index_url))
              return
  
          # add alias
          alias_data = """
          {
              "actions": [
                  {
                      "add": {
                          "index": "%s",
                          "alias": "%s"
                      }
                  }
              ]
          }
          """ % (self.index, alias)
  
          r = self.requests.post(self.url + "/_aliases", headers=HEADER_JSON, verify=False, data=alias_data)
          try:
              r.raise_for_status()
          except requests.exceptions.HTTPError as ex:
              logger.warning("Something went wrong when adding an alias on %s. Alias not set.",
                             self.anonymize_url(self.index_url))
              logger.warning(ex)
              return
  
          logger.info("Alias %s created on %s.", alias, self.anonymize_url(self.index_url))
docs: Add an alias to the index set in the elastic obj
  
          :param alias: alias to add
  
          :returns: None