### Question:
CountryRegionIndex { public boolean isValidRegion(String regionCode) { return regionCode != null && indexByBase32.containsKey(normalize(regionCode)); } CountryRegionIndex();  CountryRegionIndex(String resourceName);  CountryRegionIndex(String resourceName, String excludedName); boolean isValidRegion(String regionCode); CountryRegion getRegion(String regionCode); CountryRegion getFromBase32(String regionCodeBase32NoDash); CountryRegion matchCountryRegion(String encodedAddress); Collection<CountryRegion> countryRegions();  }### Answer:
@Test public void loading() { assertTrue(index.isValidRegion("GB-LND")); assertTrue(index.isValidRegion("IE-D")); assertTrue(index.isValidRegion("RO-AB")); assertTrue(index.isValidRegion("RO-HD")); assertFalse(index.isValidRegion("RO-HDD")); assertFalse(index.isValidRegion("askfdaf")); assertFalse(index.isValidRegion(null)); }