code: function wrap(nodes) {
    nodes = nodes || [];
    if ('string' == typeof nodes) {
      nodes = new DOMParser().parseFromString(nodes);
    }
  
    if (nodes.attrNS && nodes._related) {
      // attempt to re-wrap Collection, return it directly
      return nodes;
    } else if (nodes.documentElement) {
      nodes = [ nodes.documentElement ];
    } else if (nodes.nodeType) {
      nodes = [ nodes ];
    }
    return new Collection(nodes);
  }
docs: Wraps and returns a new collection of elements.
  
  Examples:
  
  $('<xml/>');
  
  @param {String|Node|Collection|Array} nodes XML string or DOM nodes to wrap.
  @return {Collection} The wrapped nodes.
  @api public