code: public static <K, V> TypeChecker<Map<? extends K, ? extends V>> tMap(TypeChecker<? extends K> keyChecker, Class<? extends V> valueType) {
          return tMap(keyChecker, tSimple(valueType));
      }
docs: Creates a recursing type checker for a {@link java.util.Map}.
  
  @param keyChecker The typechecker to check the keys with
  @param valueType The typechecker to check the values with
  @return a typechecker for a Map containing keys passing the specified type checker and values of the specified type