Attach (recommended) or Link to PDF file here:
PDF from #4106, https://mail.gnome.org/archives/evince-list/2013-November/pdfNC0hkVW67a.pdf.

Steps to reproduce the problem:
1. Open the PDF

What is the expected behavior?
![immagine](https://user-images.githubusercontent.com/1616846/121865567-67ca4200-ccfe-11eb-8673-1d6e863fc8d5.png)

What went wrong?
The PDF doesn't load, `TypeError: can't access property Symbol(), match is null` error is logged in the console.
constructor(attributes) {
    super(TEMPLATE_NS_ID, "subform",  true);
    this.access = getStringOption(attributes.access, [
      "open",
      "nonInteractive",
      "protected",
      "readOnly",
    ]);
    this.allowMacro = getInteger({
      data: attributes.allowMacro,
      defaultValue: 0,
      validate: x => x === 1,
    });
    this.anchorType = getStringOption(attributes.anchorType, [
      "topLeft",
      "bottomCenter",
      "bottomLeft",
      "bottomRight",
      "middleCenter",
      "middleLeft",
      "middleRight",