import “selection”;

d3_selectionPrototype.order = function() {

for (var j = -1, m = this.length; ++j < m;) {
  for (var group = this[j], i = group.length - 1, next = group[i], node; --i >= 0;) {
    if (node = group[i]) {
      if (next && next !== node.nextSibling) next.parentNode.insertBefore(node, next);
      next = node;
    }
  }
}
return this;

};