Align some nav-pills elements to right in Bootstrap 4

Question

I am using Bootstrap 4-beta2's nav-pills to implement tabbed interface.

How do I align some elements to the right of the screen?

Setting ml-auto on the last li item does not work. Splitting up the ul in two ul's does not work either because it allows tabright to be active at the same time as, say, tableft1.

<nav class="fixed-top bg-dark">
    <div class="navbar">
        <a class="navbar-brand" href="#tabmain">Brand</a>
        <ul class="nav nav-pills mr-auto">
            <li class="nav-pill active"><a class="nav-link" href="#tableft1" data-toggle="pill">TabLeft1</a></li>
            <li class="nav-pill"><a class="nav-link" href="#tableft2" data-toggle="pill">TabLeft2</a></li>
            <li class="nav-pill"><a class="nav-link" href="#tabright" data-toggle="pill">TabRight</a></li>
        </ul>
    </div>
</nav>

Answer 1

Turns out the navbar is flex, so flex-specific classes are helping:

<nav class="fixed-top bg-dark">
    <div class="navbar justify-content-start flex-nowrap">
        <a class="navbar-brand" href="#tabmain">Brand</a>
        <ul class="nav nav-pills w-100">
            <li class="nav-pill active"><a class="nav-link" href="#tableft1" data-toggle="pill">TabLeft1</a></li>
            <li class="nav-pill"><a class="nav-link" href="#tableft2" data-toggle="pill">TabLeft2</a></li>
            <li class="nav-pill ml-auto"><a class="nav-link" href="#tabright" data-toggle="pill">TabRight</a></li>
        </ul>
    </div>
</nav>