old_contents: function extend (target) {
    var arg
    var key
    var len = arguments.length
    var i = 0
  
    while (++i < len) {
      arg = arguments[i]
      if (!arg) continue
  
      for (key in arg) {
        if (arg.hasOwnProperty(key)) target[key] = arg[key]
      }
    }
    return target
  }
  
  module.exports = extend
  
new_contents: function extend (target) {
    var arg
    var key
    var len = arguments.length
    var i = 0
  
    while (++i < len) {
      arg = arguments[i]
      if (!arg) continue
  
      for (key in arg) {
        if (arg.hasOwnProperty(key)) target[key] = arg[key]
      }
    }
  
    return target
  }
  
  module.exports = extend
  
subject: update object/extend -- minor edit