### Question:
CommonCourtUtils { public static String extractAppealCourtNumber(String courtCode) { Preconditions.checkArgument(isValidCommonCourtCode(courtCode)); return courtCode.substring(2, 4); } private  CommonCourtUtils(); static boolean isValidCommonCourtCode(String courtCode); static String extractAppealCourtNumber(String courtCode); static String extractRegionalCourtNumber(String courtCode); static String extractDistrictCourtNumber(String courtCode); static CommonCourtType extractType(String courtCode);  }### Answer:
@Test public void extractAppealCourtCode() { assertEquals("60", CommonCourtUtils.extractAppealCourtNumber("15600203")); }