element.toggleClass() does not remove one of classnames

[kurumpa]

when starting with
someElement == [<div class="class1"></div>]
after calling someElement.toggleClass("class1 class2");
expected:
someElement == [<div class="class2"></div>]
actual:
someElement == [<div class="class1 class2"></div>]
using AngularJS v1.0.8