Append items to navbar

[Qumeric]

As "Getting Started" page says:

Items are added by simply passing them to the Navbar-constructor. This is purely convenience, instead it is possible to append to the items attribute of topbar as well.

I have tried to append to the items attribute and failed. Eventually I figured out that this attribute is a tuple so it's impossible to append.
I have found a simple workaround

navbar = Navbar('', ...)
navbar.items = list(navbar.items)

but it doesn't seem like a proper way to do things. Shouldn't Navbar.items be a list instance by default?

[mbr]

That's a valid point and either the documentation or the implementation need to change here.