'parents' is broken about argparse HOT 2 CLOSED

var ArgumentParser = module.exports = function ArgumentParser(options)
...
  // add parent arguments and defaults
var that = this; // like coffeescript =>
  options.parents.forEach(function (parent) {
    that._addContainerActions(parent);  // this to that
    if (parent._defaults !== undefined) {
      for (var defaultKey in parent._defaults) {
        if (parent._defaults.hasOwnProperty(defaultKey)) {
          that._defaults[defaultKey] = parent._defaults[defaultKey];
        }
      }
    }
  });

ActionContainer.prototype._addContainerActions = function (container) {
  // collect groups by titles
  var titleGroupMap = {};
  this._actionGroups.forEach(function (group) {
    // if (titleGroupMap.indexOf(group.title) >= 0) {  // wrong, titleGroupMap is obj, not array
    // if group.title in title_group_map:
    if (_.has(titleGroupMap, group.title)) {  // correct test
      throw new Error(_.str.sprintf('Cannot merge actions - two groups are named "%(group.title)s".', group));
    }
    titleGroupMap[group.title] = group;
  });
...
  // map each action to its group
  var groupMap = {};
  var that = this;  // as in coffeescript =>  
  container._actionGroups.forEach(function (group) {
    // if a group with the title exists, use that, otherwise
    // create a new group matching the container's group
    // if (titleGroupMap.indexOf(group.title) < 0) {  // wrong translation of python 'in'
    if (!_.has(titleGroupMap, group.title)) {  // correction
      titleGroupMap[group.title] = that.addArgumentGroup({  // correction, this to that
        title: group.title,
        description: group.description
      });
    }

parent_parser = new ArgumentParser({addHelp:false});
// note addHelp:false to prevent duplication of the -h option
parent_parser.addArgument(['--parent'], {type:'int',description:'parent', });

foo_parser = new ArgumentParser({parents:[parent_parser],description:'child1', });
foo_parser.addArgument(['foo']);
args = foo_parser.parseArgs(['--parent', '2', 'XXX']);
console.log(args);
// Namespace(foo='XXX', parent=2)

bar_parser = new ArgumentParser({parents:[parent_parser],description:'child2', });
bar_parser.addArgument(['--bar']);
args = bar_parser.parseArgs(['--bar', 'YYY']);
console.log(args)
// Namespace(bar='YYY', parent=None)