code: protected DateTimeException _peelDTE(DateTimeException e) {
          while (true) {
              Throwable t = e.getCause();
              if (t != null && t instanceof DateTimeException) {
                  e = (DateTimeException) t;
                  continue;
              }
              break;
          }
          return e;
      }
docs: Helper method used to peel off spurious wrappings of DateTimeException
  
  @param e DateTimeException to peel
  
  @return DateTimeException that does not have another DateTimeException as its cause.