def each_row(&block)
      return self.to_enum(:each_row) unless block_given?
      @index.each.with_index do |el, i|
        row_arr = @data.map{|darr| darr[i]}
        row = Mikon::Row.new(@labels, row_arr, @index[i])
        block.call(row)
      end
    end
def each_row(&block)
      return self.to_enum(:each_row) unless block_given?
      @index.each.with_index do |el, i|
        row_arr = @data.map{|darr| darr[i]}
        row = Mikon::Row.new(@labels, row_arr, @index[i])
        block.call(row)
      end
    end
Iterate row