docs: function getOptionLabel(option, labelKey) {
    let optionLabel;
  
    if (typeof option === 'string') {
      optionLabel = option;
    }
  
    if (isPlainObject(option)) {
      if (typeof labelKey === 'string') {
        optionLabel = option[labelKey];
      } else if (isFunction(labelKey)) {
        optionLabel = labelKey(option);
      }
    }
  
    invariant(
      typeof optionLabel === 'string',
      'One or more options does not have a valid label string. Check the ' +
      '`labelKey` prop to ensure that it matches the correct option key and ' +
      'provides a string for filtering and display.'
    );
  
    return optionLabel;
  }