def ele(row, col, val = nil)
      if val.nil?
        get_ele(row, col)
      else
        set_ele(row, col, val)
      end
    end
def ele(row, col, val = nil)
      if val.nil?
        get_ele(row, col)
      else
        set_ele(row, col, val)
      end
    end
Access an element
 @overload ele(row, col)
   Get an element
   @param row [String]
   @param col [String]
   @return [String]
 @overload ele(row, col, val)
   Set an element
   @param row [String]
   @param col [String]
   @param val [String]
   @return [Table]