# File lib/sup/keymap.rb, line 78
  def help_lines except_for={}, prefix=""
    lines = [] # :(
    @order.each do |action, help, keys|
      valid_keys = keys.select { |k| !except_for[k] }
      next if valid_keys.empty?
      case action
      when Symbol
        lines << [valid_keys.map { |k| prefix + Keymap.keysym_to_string(k) }.join(", "), help]
      when Keymap
        lines += action.help_lines({}, prefix + Keymap.keysym_to_string(keys.first))
      end
    end.compact
    lines
  end