def long_out io , level
      indent = " " * level
      @children.each_with_index do |child , i|
        io.write "\n#{indent}" unless i == 0
        io.write "- "
        child.out(io , level + 1)
      end
    end
def long_out io , level
      indent = " " * level
      @children.each_with_index do |child , i|
        io.write "\n#{indent}" unless i == 0
        io.write "- "
        child.out(io , level + 1)
      end
    end
Arrays start with the minus on each line "-"
 and each line has the value