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: data_converter.rb
    path of file: ./repos/truffleruby/lib/truffle/ffi
    
    the code of the file until where you have to start completion: #
# Copyright (C) 2008-2010 Wayne Meissner
#
# This file is part of ruby-ffi.
#
# All rig
    
    def native_type(type = nil)
      if type
        @native_type = FFI.find_type(type)
      else
        native_type = @native_type
        unless native_type
          raise NotImplementedError, 'native_type method not overridden and no native_type set'
        end