function getHandler(protocol) {
  if (!protocol) {
    throw new NotFoundError(`Tasmota: "${protocol}" protocol is not managed`);
  }

  const handler = this.protocols[protocol];
  if (!handler) {
    throw new NotFoundError(`Tasmota: "${protocol}" protocol is not managed`);
  }
  return handler;
}
@description Get handler according to requested protocol.
@param {string} protocol - Protocol to get handler.
@returns {object} Requested handler.
@example
getHandler('http');