message: Make type happy around Assets
diff: @@ -100,8 +100,15 @@ export default class Builder implements BuilderInterface {
  return this.buildCard(url);
  }
  - copyAssets(cardURL: string, assets: Asset[], files: RawCard['files']): void {
  + copyAssets(
  + cardURL: string,
  + assets: (Asset | undefined)[],
  + files: RawCard['files']
  + ): void {
  for (const asset of assets) {
  + if (!asset) {
  + continue;
  + }
  this.cache.writeAsset(cardURL, asset.path, files[asset.path]);
  }
  }
  