     }
 
     ///
-    /// failure (rejected or cancelled) + closure returning **task**
+    /// `failure` (rejected or cancelled) + closure returning **task**.
+    /// (synonym for `flatMapError` in functional programming)
     ///
     /// - e.g. task.failure { errorInfo -> NextTaskType in ... }
     /// - e.g. task.failure { error, isCancelled -> NextTaskType in ... }
+    ///
+    /// - Returns: New `Task`
     ///
     public func failure<Progress2, Error2>(failureClosure: ErrorInfo -> Task<Progress2, Value, Error2>) -> Task<Progress2, Value, Error2>
     {

        }.name("\(self.name)-failure")
    }
    
    public func on(success success: (Value -> Void)? = nil, failure: (ErrorInfo -> Void)? = nil) -> Self
    {
        var dummyCanceller: Canceller? = nil

    }
    
    ///
    /// Create fulfilled task (non-paused)
    ///
    /// - e.g. Task<P, V, E>(value: someValue)
    ///
