         :param: username The resource owner's username.
         :param: password The resource owner's password.
 
-        :returns: A `SignalProducer` that, when started, creates and sends a
-            signal that completes when the request finishes successfully or
-            sends an error of the request finishes with an error.
+        :returns: A `SignalProducer` that, when started, creates a signal that
+            completes when the request finishes successfully or sends an error
+            if the request finishes with an error.
     */
     public func requestAccessToken(#username: String, password: String) -> SignalProducer<Void, NSError> {
         return SignalProducer { observer, disposable in

        :param: password The resource owner's password.

        :returns: A signal that sends a `RACUnit` and completes when the
            request finishes successfully or sends an error of the request
            finishes with an error.
    */
    @objc

    
        :param: request An unauthenticated NSURLRequest.
    
        :returns: A `SignalProducer` that, when started, creates a signal that
            sends the authenticated request on success or an error if the
            request could not be authenticated.
    */
    public func authenticateRequest(request: NSURLRequest) -> SignalProducer<NSURLRequest, NSError> {
        return SignalProducer { observer, disposable in
