Template property "css" explained

I am trying to understand the “css” property on a DataView template. I have tried setting this value to a class in my css and putting inline css in the value. I see no impact. What am I missing? Please explain.

css property of the type applies dhx_dataview_[css]_item css class to a parent container of an item. For example:

color:red !important;

.... data = new dhtmlXDataView({ container:"data_container", type:{ template: "#text#", css:"my_css", height:40 } }); ...[/code]