_getElementOption(option) {
    // If column width is a string, treat is as a selector and search for the
    // sizer element within the outermost container
    if (typeof option === 'string') {
      return this.element.querySelector(option);
    }

    // Check for an element
    if (option && option.nodeType && option.nodeType === 1) {
      return option;
    }

    // Check for jQuery object
    if (option && option.jquery) {
      return option[0];
    }

    return null;
  }
Retrieve an element from an option.
@param {string|jQuery|Element} option The option to check.
@return {?Element} The plain element or null.
@private