public static String classString(int flags) {
    return humanHelper(flags, CLASS_FLAGS, CONV_CLASS);
  }
Returns a human-oriented string representing the given access flags, as defined on classes (not
fields or methods).

@param flags the flags
@return {@code non-null;} human-oriented string
android/android_framework/dex-maker/src/main/java/com/android/dx/rop/code/AccessFlags.java