code: @Override
      public CronDefinitionBuilder and() {
          final boolean zeroInRange = constraints.createConstraintsInstance().isInRange(0);
          cronDefinitionBuilder
                  .register(new DayOfWeekFieldDefinition(fieldName, constraints.createConstraintsInstance(), optional, new WeekDay(mondayDoWValue, zeroInRange)));
          return cronDefinitionBuilder;
      }
docs: Registers CronField in ParserDefinitionBuilder and returns its instance.
  
  @return ParserDefinitionBuilder instance obtained from constructor