code: def exec_appcommand_post(self, attribute_list):
          
          # Prepare POST XML body for AppCommand.xml
          post_root = ET.Element("tx")
  
          for attribute in attribute_list:
              # Append tags for each attribute
              item = ET.Element("cmd")
              item.set("id", "1")
              item.text = attribute
              post_root.append(item)
  
          # Buffer XML body as binary IO
          body = BytesIO()
          post_tree = ET.ElementTree(post_root)
          post_tree.write(body, encoding="utf-8", xml_declaration=True)
  
          # Query receivers AppCommand.xml
          try:
              res = self.send_post_command(
                  self._urls.appcommand, body.getvalue())
          except requests.exceptions.RequestException:
              _LOGGER.error("No connection to %s end point on host %s",
                            self._urls.appcommand, self._host)
              body.close()
          else:
              # Buffered XML not needed anymore: close
              body.close()
  
              try:
                  # Return XML ElementTree
                  root = ET.fromstring(res)
              except (ET.ParseError, TypeError):
                  _LOGGER.error(
                      "End point %s on host %s returned malformed XML.",
                      self._urls.appcommand, self._host)
              else:
                  return root
docs: Prepare and execute a HTTP POST call to AppCommand.xml end point.
  
          Returns XML ElementTree on success and None on fail.