def children_are_up_to_date(self):
        """Alternate check for whether the Node is current:  If all of
        our children were up-to-date, then this Node was up-to-date, too.

        The SCons.Node.Alias and SCons.Node.Python.Value subclasses
        rebind their current() method to this method."""
        # Allow the children to calculate their signatures.
        self.binfo = self.get_binfo()
        if self.always_build:
            return None
        state = 0
        for kid in self.children(None):
            s = kid.get_state()
            if s and (not state or s > state):
                state = s
        return (state == 0 or state == SCons.Node.up_to_date)
Alternate check for whether the Node is current:  If all of
        our children were up-to-date, then this Node was up-to-date, too.

        The SCons.Node.Alias and SCons.Node.Python.Value subclasses
        rebind their current() method to this method.