function parseExternalId(externalId) {
  const parsedExternalId = externalId.split(':');
  const deviceId = parsedExternalId[1];
  return deviceId;
}
@description Parse the external id and return the plug ID.
@param {string} externalId - External id of the device.
@returns {string} Return the deviceId.
@example
parseExternalId('tp-link-plug:1');