 	/// - note: If `signal` fails, the returned signal will forward that failure
 	///         immediately.
 	///
-	/// - warning: `Interrupted` events on inner producers will be treated like 
+	/// - warning: `Interrupted` events on inner producers will be treated like
 	///            `Completed` events on inner producers.
 	@warn_unused_result(message="Did you forget to call `observe` on the signal?")
 	public func flatten(strategy: FlattenStrategy) -> Signal<Value.Value, Error> {

}

extension SignalType where Value: SignalProducerType, Error == Value.Error {
	/// Returns a signal which sends all the values from producer signal emitted from
	/// `signal`, waiting until each inner producer completes before beginning to
	/// send the values from the next inner producer.
	///
	/// - note: If any of the inner producers fail, the returned signal will
	///         forward that failure immediately

}

extension SignalProducerType where Value: SignalProducerType, Error == NoError, Value.Error == NoError {
	/// Flattens the inner producers sent upon `producer` (into a single
	/// producer of values), according to the semantics of the given strategy.
	///
	/// - warning: `Interrupted` events on inner producers will be treated like
