code: def handle_modifier_down(self, modifier):
          
          _logger.debug("%s pressed", modifier)
          if modifier in (Key.CAPSLOCK, Key.NUMLOCK):
              if self.modifiers[modifier]:
                  self.modifiers[modifier] = False
              else:
                  self.modifiers[modifier] = True
          else:
              self.modifiers[modifier] = True
docs: Updates the state of the given modifier key to 'pressed'