'Button press handler and validator'

def press(self, event):

    if (not self.ignore(event)):
        event = self._clean_event(event)
        self.eventpress = event
        self._prev_event = event
        key = (event.key or u'')
        key = key.replace(u'ctrl', u'control')
        if (key == self.state_modifier_keys[u'move']):
            self.state.add(u'move')
        self._press(event)
        return True
    return False
