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: option.rb
    path of file: ./repos/stackneveroverflow/vendor/bundle/ruby/2.3.0/gems/thor-0.19.4/lib/thor/parser
    
    the code of the file until where you have to start completion: class Thor
  class Option < Argument #:nodoc:
    attr_reader :aliases, :group, :
    
    def validate_default_type!
      default_type = case @default
      when nil
        return
      when TrueClass, FalseClass
        required? ? :string : :boolean
      when Numeric
        :numeric
      when Symbol
        :string
      when Hash, Array, String
        @default.class.name.downcase.to_sym
      end