private static boolean isCandidate(Type[] argTypes, Type returnType) {
    if (isStringType(returnType)) {
      return true;
    }
    for (Type argType : argTypes) {
      if (isStringType(argType)) {
        return true;
      }
    }
    return false;
  }
private static boolean isCandidate(Type[] argTypes, Type returnType)