Place @widgets under the blitting hand of the Container(). Each arg 
        must be a Widget(), a fellow Container(), or an iterable. Else, things 
        get ugly...

def add(self, *widgets):
        '''
        Place @widgets under the blitting hand of the Container(). Each arg 
        must be a Widget(), a fellow Container(), or an iterable. Else, things 
        get ugly...
        '''
        for w in widgets:
            if is_widget(w):
                if w not in self.widgets:
                    self.widgets.add(w)
                    w.add_internal(self)
            elif is_container(w):
                if w not in self.containers:
                    self.containers.add(w)
                    w.add_internal(self)
            else:
                # If it isn't an iterable, we'll get an error here.
                # Desired effect.
                self.add(*w)