code: protected Throwable composeErrors(Throwable... errors) {
  
      if (errors == null) {
        return new NullPointerException("errors");
      } else if (errors.length == 1) {
        return errors[0];
      } else {
        return new ComposedException(errors);
      }
    }
docs: Returns a single exception containing all information of the given {@code errors}.
  
  @param errors are the errors to compose.
  @return a single exception containing all errors.