code: public int compareTo(ReadablePartial partial) {
          if (partial == null) {
              throw new IllegalArgumentException("The partial must not be null");
          }
          int thisValue = get();
          int otherValue = partial.get(getFieldType());
          if (thisValue < otherValue) {
              return -1;
          } else if (thisValue > otherValue) {
              return 1;
          } else {
              return 0;
          }
      }
docs: Compare this field to the same field on another partial instant.
  <p>
  The comparison is based on the value of the same field type, irrespective
  of any difference in chronology. Thus, if this property represents the
  hourOfDay field, then the hourOfDay field of the other partial will be queried
  whether in the same chronology or not.
  
  @param partial  the partial to compare to
  @return negative value if this is less, 0 if equal, or positive value if greater
  @throws IllegalArgumentException if the partial is null
  @throws IllegalArgumentException if the partial doesn't support this field