code: def merge(cls, components):
      
      # Note that action of the merged component is EXTEND until the first REPLACE is encountered.
      # This guarantees associativity.
      action = cls.EXTEND
      val = {}
      for component in components:
        if component.action is cls.REPLACE:
          val = component.val
          action = cls.REPLACE
        elif component.action is cls.EXTEND:
          val.update(component.val)
        else:
          raise ParseError('Unknown action for dict value: {}'.format(component.action))
      return cls(action, val)
docs: Merges components into a single component, applying their actions appropriately.
  
      This operation is associative:  M(M(a, b), c) == M(a, M(b, c)) == M(a, b, c).
  
      :param list components: an iterable of instances of DictValueComponent.
      :return: An instance representing the result of merging the components.
      :rtype: `DictValueComponent`