def format
      rows = @children
      rows = @children[1..-1] if @skip_first_row
      rows ||= []
      rows = rows.collect { |row| row.format }.join("\n")

      return nil if rows.length == 0
      rows
    end
def format
      rows = @children
      rows = @children[1..-1] if @skip_first_row
      rows ||= []
      rows = rows.collect { |row| row.format }.join("\n")

      return nil if rows.length == 0
      rows
    end
TODO: rename this to_s