/// <summary>
    ///   <para>The color scheme used by the widget.</para>
    /// </summary>
    /// <param name="widget">Widget to call method on.</param>
    /// <param name="colorScheme">Color scheme of widget.</param>
    /// <returns>Reference to the current widget.</returns>
    /// <exception cref="ArgumentNullException">If <paramref name="widget"/> is a <c>null</c> reference.</exception>
    /// <seealso cref="IFacebookRecommendationsFeedWidget.ColorScheme(string)"/>
    public static IFacebookRecommendationsFeedWidget ColorScheme(this IFacebookRecommendationsFeedWidget widget, FacebookColorScheme colorScheme)
    {
      Assertion.NotNull(widget);

      return widget.ColorScheme(colorScheme.ToString().ToLowerInvariant());
    }
    /// <summary>
    ///   <para>The color scheme used by the button.</para>
    /// </summary>
    /// <param name="widget">Widget to call method on.</param>
    /// <param name="colorScheme">Color scheme of button.</param>
    /// <returns>Reference to the current widget.</returns>
    /// <exception cref="ArgumentNullException">If <paramref name="widget"/> is a <c>null</c> reference.</exception>
    /// <seealso cref="IFacebookFollowButtonWidget.ColorScheme(string)"/>
    public static IFacebookFollowButtonWidget ColorScheme(this IFacebookFollowButtonWidget widget, FacebookColorScheme colorScheme)
    {
      Assertion.NotNull(widget);

      return widget.ColorScheme(colorScheme.ToString().ToLowerInvariant());
    }
        /// <summary>
        ///   <para>The color scheme used by the widget.</para>
        /// </summary>
        /// <param name="widget">Widget to call method on.</param>
        /// <param name="colorScheme">Color scheme of widget.</param>
        /// <returns>Reference to the current widget.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="widget"/> is a <c>null</c> reference.</exception>
        /// <seealso cref="IFacebookActivityFeedWidget.ColorScheme(string)"/>
        public static IFacebookActivityFeedWidget ColorScheme(this IFacebookActivityFeedWidget widget, FacebookColorScheme colorScheme)
        {
            Assertion.NotNull(widget);

            return(widget.ColorScheme(colorScheme.ToString().ToLowerInvariant()));
        }
        /// <summary>
        ///   <para>Color scheme used by the button.</para>
        /// </summary>
        /// <param name="widget">Widget to call method on.</param>
        /// <param name="scheme">The color scheme for the button.</param>
        /// <returns>Reference to provided <paramref name="widget"/>.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="widget"/> is a <c>null</c> reference.</exception>
        /// <seealso cref="IFacebookLikeButtonWidget.ColorScheme(string)"/>
        public static IFacebookLikeButtonWidget ColorScheme(this IFacebookLikeButtonWidget widget, FacebookColorScheme scheme)
        {
            Assertion.NotNull(widget);

            return(widget.ColorScheme(scheme.ToString().ToLowerInvariant()));
        }