How to call a static method without an instance?

How does one call a static class method for Dz* classes?

It works as expected on ECMAScript classes:

Array.isArray([])
Date.now()
String.fromCharCode(65)

But fails for all the DAZ classes:

DzDir.cleanPath("/Path")
DzUri.fromLocalFilename("/Path")
DzVersion.fromString("1.0")