// TODO insert(node, function)?

// TODO insert(function, string)?

// TODO insert(function, function)?

d3_selectionPrototype.insert = function(name, before) {

  name = d3.ns.qualify(name);

  function insert() {

    return this.insertBefore(

        document.createElement(name),

        d3_select(before, this));

  }

  function insertNS() {

    return this.insertBefore(

        document.createElementNS(name.space, name.local),

        d3_select(before, this));

  }

  return this.select(name.local ? insertNS : insert);

};