     
         :param: request An unauthenticated NSURLRequest.
     
-        :returns: A `SignalProducer` that, when started, creates and sends a
-            signal that sends the authenticated request on success or an error
-            when the request could not be authenticated.
+        :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

        :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.
    */
    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 if the request
            finishes with an error.
    */
    @objc
