Change static_template function from derived class

> class SearchGrid extends Grid {
> //grid function
> }
//ITEM WRAPPER HELPER CLASS USE FOR Lightning GRID COMPONENT
 static _template() {
        return {
        //want to add collision true here
            clipbox: true
        }
    }

i just want to change ItemWrapper static _template function, just want add one key “collision:true”, How can i modify this template function from grid class?