title: Swift - Get list of countries -> fatal error: Can't unwrap Optional.None
body: <p>I asked few days ago about how to get a list of countries in Swift, and you solved the first part of it (here: <a href="https://stackoverflow.com/questions/24315741/swift-get-list-of-countries">Swift - Get list of countries</a>), but I am not able to get the final countries list because it gives an error:</p>
  
  <pre><code>var countries: NSMutableArray = NSMutableArray()
  countries = NSMutableArray(capacity: (NSLocale.ISOCountryCodes().count))
  for countryCode : AnyObject in NSLocale.ISOCountryCodes() {
    let dictionary : NSDictionary = NSDictionary(object:countryCode, forKey:NSLocaleCountryCode)
    let identifier : NSString     = NSLocale.localeIdentifierFromComponents(dictionary)
    // next line - fatal error: Can't unwrap Optional.None
    let country    : NSString     = 
      NSLocale.currentLocale().displayNameForKey(NSLocaleIdentifier, value: identifier)
    countries.addObject(country)
  }
  println(countries)
  </code></pre>
  
  <p>What does the "fatal error: Can't unwrap Optional.None" error mean? I've been trying and searching about it but I haven't find the solution yet :/</p>
  
  <p>Million thanks :)</p>