code: def packvalue(value, *properties):
      '''
      Store a specified value to specified property path. Often used in nstruct "init" parameter.
      
      :param value: a fixed value
      
      :param properties: specified field name, same as sizefromlen.
      
      :returns: a function which takes a NamedStruct as parameter, and store the value to property path.
      
      '''
      def func(namedstruct):
          v = namedstruct._target
          for p in properties[:-1]:
              v = getattr(v, p)
          setattr(v, properties[-1], value)
      return funf packvalue(value, *properties):
      '''
      Store a specified value to specified property path. Often used in nstruct "init" parameter.
      
      :param value: a fixed value
      
      :param properties: specified field name, same as sizefromlen.
      
      :returns: a function which takes a NamedStruct as parameter, and store the value to property path.
      
      '''
      def func(namedstruct):
          v = namedstruct._target
          for p in properties[:-1]:
              v = getattr(v, p)
          setattr(v, properties[-1], value)
      return func
docs: Store a specified value to specified property path. Often used in nstruct "init" parameter.
      
      :param value: a fixed value
      
      :param properties: specified field name, same as sizefromlen.
      
      :returns: a function which takes a NamedStruct as parameter, and store the value to property path.