You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: combobox_proxy.rb
    path of file: ./repos/glimmer-dsl-libui/lib/glimmer/libui/control_proxy
    
    the code of the file until where you have to start completion: # Copyright (c) 2021-2024 Andy Maleh
#
# Permission is hereby granted, free of
    
        def selected(value = nil)
          if value.nil?
            super()
          else
            if value.is_a?(String)
              super(items.index(value).to_i)
            else
              super
            end