Add & Remove Session Headers in Alamofire in Swift 2.0

Headers.Swift

func addSessionHeader(key: String, value: String) {
  var headers:[NSObject : AnyObject]
  if let existingHeaders = 
    alamofireManager.session.configuration.HTTPAdditionalHeaders as? [String: String] {
    headers = existingHeaders
  } else {
    headers = Manager.defaultHTTPHeaders
  }
  headers[key] = value
  let config = alamofireManager.session.configuration
  config.HTTPAdditionalHeaders = headers
  print(config.HTTPAdditionalHeaders)
  alamofireManager = Alamofire.Manager(configuration: config)
}

func removeSessionHeaderIfExists(key: String) {
  let config = alamofireManager.session.configuration
  if var headers = config.HTTPAdditionalHeaders {
    headers.removeValueForKey(key)
    config.HTTPAdditionalHeaders = headers
    alamofireManager = Alamofire.Manager(configuration: config)
  }
}