     {
         guard let queryString = responseURL.query,
             let parameters = self.parametersFromQueryString(queryString),
-            let code = parameters["code"],
-            let state = parameters["state"]
+            let code = parameters[self.dynamicType.CodeKey],
+            let state = parameters[self.dynamicType.StateKey]
         else
         {
             let errorDescription = "Could not retrieve parameters from code grant response"

    
    private func setupRequestSerializer(account account: VIMAccountNew) throws
    {
        guard let authToken = account.accessToken
            else
        {
            let errorDescription = "AuthenticationController did not recieve an access token with account response"

    
    func codeGrantAuthorizationURL() -> NSURL
    {
        let parameters = [self.dynamicType.ResponseTypeKey: self.dynamicType.CodeKey,
                          self.dynamicType.ClientIDKey: self.configuration.clientKey,
                          self.dynamicType.RedirectURIKey: self.codeGrantRedirectURI,
                          self.dynamicType.ScopeKey: Scope.combine(self.configuration.scopes),
                          self.dynamicType.StateKey: self.dynamicType.state]
        
        var error: NSError?
        guard let urlString = VimeoBaseURLString?.URLByAppendingPathComponent(self.dynamicType.CodeGrantAuthorizationPath).absoluteString
        else
        {
            fatalError("Could not make code grant auth URL")
