The spec for this action:
https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#G11.2111850
An example of a form using this action:
https://www2.illinois.gov/rev/forms/reg/Documents/reg-1-mr.pdf
signatureGetModifications() {}
  signatureGetSeedValue() {}
  signatureInfo() {}
  signatureSetSeedValue() {}
  signatureSign() {}
  signatureValidate() {}
  _isButton() {
    return false;
  }
  _runActions(event) {
    const eventName = event.name;
    if (!this._actions.has(eventName)) {
      return false;
    }
    const actions = this._actions.get(eventName);
    try {
      for (const action of actions) {
        
        this._globalEval(action);
      }
    } catch (error) {
      event.rc = false;
      throw error;
    }
    return true;
  }
}
class RadioButtonField extends Field {