var zones = svg_layer.selectAll( 'path[class=switch]' );

<path class="switch" fill="none" stroke="#009640" stroke-width="0.7087" d="
    M236.6,75c0-14.1,1,75z"></path>

<path class="switch used" fill="none" stroke="#009640" stroke-width="0.7087" d="
    M236.6,75c0-14.1,1,75z"></path>

Snap.selectAll = function (query) {
    var nodelist = glob.doc.querySelectorAll(query),
        set = (Snap.set || Array)();
    for (var i = 0; i < nodelist.length; i++) {
        set.push(wrap(nodelist[i]));
    }
    return set;
    };