# File lib/rdoc/task.rb, line 170
  def check_names names
    return unless Hash === names

    invalid_options =
      names.keys.map { |k| k.to_sym } - [:rdoc, :clobber_rdoc, :rerdoc]

    unless invalid_options.empty? then
      raise ArgumentError, "invalid options: #{invalid_options.join ', '}"
    end
  end