def is_up_to_date(self):
        if self.builder is not MkdirBuilder and not self.exists():
            return 0
        up_to_date = SCons.Node.up_to_date
        for kid in self.children():
            if kid.get_state() > up_to_date:
                return 0
        return 1
If any child is not up-to-date, then this directory isn't,
dataset/ETHPy150Open kayhayen/Nuitka/nuitka/build/inline_copy/lib/scons-2.3.2/SCons/Node/FS.py/Dir.is_up_to_date