def remove(self, elem):
        """Remove a requirement.

        :param elem: a string or :class:`Requirement` instance.
        """
        if isinstance(elem, text_type):
            for requirement in self:
                if requirement.package == elem:
                    return super(Requirements, self).remove(requirement)
        return super(Requirements, self).remove(elem)
def handleevent(self):
        """
        Event-handler for the 'widgets' demo
        """
        while True:
            event = self.dialog.waitForEvent()
            if event.eventType() == yui.YEvent.CancelEvent:
                self.dialog.destroy()
                break
            if event.widget() == self.closebutton:
                info = Info("Quit confirmation", 1, "Are you sure you want to quit?")
                if self.ask_YesOrNo(info):
                    self.dialog.destroy()
                    break
            if event.widget() == self.aboutbutton:
                self.aboutDialog()