def to_s
      rendered_rows = [separator] + text_table_rows.map(&:to_s) + [separator]
      rendered_rows.unshift [separator, text_table_head.to_s] if head
      rendered_rows << [text_table_foot.to_s, separator] if foot
      rendered_rows.join
    end
def to_s
      rendered_rows = [separator] + text_table_rows.map(&:to_s) + [separator]
      rendered_rows.unshift [separator, text_table_head.to_s] if head
      rendered_rows << [text_table_foot.to_s, separator] if foot
      rendered_rows.join
    end
Renders a pretty plain-text table.