public RomanNumeralConverter(IConvertSingleNumerals single_numeral_converter)
 {
     this.single_numeral_converter = single_numeral_converter;
 }
 public SingleNumeralConverter(RomanNumeral the_numeral, IConvertSingleNumerals next_converter)
 {
     this.the_numeral = the_numeral;
     this.next_converter = next_converter;
 }