code: public Property property(DateTimeFieldType fieldType) {
          if (fieldType == null) {
              throw new IllegalArgumentException("The DateTimeFieldType must not be null");
          }
          if (isSupported(fieldType) == false) {
              throw new IllegalArgumentException("Field '" + fieldType + "' is not supported");
          }
          return new Property(this, fieldType.getField(getChronology()));
      }
docs: Gets the property object for the specified type, which contains many
  useful methods.
  
  @param fieldType  the field type to get the chronology for
  @return the property object
  @throws IllegalArgumentException if the field is null or unsupported