title: How to initialize a custom class instance that conforms to NSCoding?
body: <p>I'm trying to use NSKeyedArchiver to store custom class instance.</p>
  
  <pre><code>class feedBack: NSObject, NSCoding {
  
  var choiceA = 0
  var choiceB = 0
  var choiceC = 0
  var choiceD = 0
  var choiceNULL = 0
  var sheetName = ""
  
  func encodeWithCoder(aCoder: NSCoder) {
      aCoder.encodeObject(self.choiceA, forKey: "choiceA")
      aCoder.encodeObject(self.choiceB, forKey: "choiceB")
      aCoder.encodeObject(self.choiceC, forKey: "choiceC")
      aCoder.encodeObject(self.choiceD, forKey: "choiceD")
      aCoder.encodeObject(self.choiceNULL, forKey: "choiceNULL")
      aCoder.encodeObject(self.sheetName, forKey: "sheetName")
  }
  
  required init(coder aDecoder: NSCoder) {
      self.choiceA = aDecoder.decodeObjectForKey("choiceA") as! Int
      self.choiceB = aDecoder.decodeObjectForKey("choiceB") as! Int
      self.choiceC = aDecoder.decodeObjectForKey("choiceC") as! Int
      self.choiceD = aDecoder.decodeObjectForKey("choiceD") as! Int
      self.choiceNULL = aDecoder.decodeObjectForKey("choiceNULL") as! Int
      self.sheetName = aDecoder.decodeObjectForKey("sheetName") as! String
  
  
  }
  
  
  }
  </code></pre>
  
  <p>Before <code>feedBack</code> conforms to NSCoding, I use <code>var fb = feedBack()</code> to create a new instance of feedBack. 
  Now the compiler throws <code>Missing argument for parameter coder in call</code> error.</p>
  
  <p>Since the <code>initWithCoder</code> is required, how do I call the previous initializer with no parameter?</p>