background color according value with the row grouping plugin

avb

Hello,
I use the row grouping datatable plugin. On the following script i have a background color for each new rows of the group
according to the name of the group category ( test, test1, test2 )

That s not what i want, I would like to add a background color directly on the row of the group.
ex : when the group name "test2" is deteted, i would like to add a background color on it.

Have you got an idea?
thank you

 api.column(3, {page:'current'} ).data().each( function ( group, i ) {
                if ( last !== group ) {
                    $(rows).eq( i ).before(
                            '<tr><td class="espace" colspan="5"></td></tr>',
                        '<tr class="group"><td colspan="5">'+group+'</td></tr>'
                    );
                
                    last = group;
                }                 
                
            } );         

  "createdRow": function ( row, data, dataIndex )   {
            if ( data[3] == "test" ) {
                $(row).addClass('red');}
                
            if ( data[3] == "Test1" ) {
                $(row).addClass('yellow');}
           
            if ( data[3] == "Test2" ) {
                $(row).addClass('grey');}

avb

no one ?