static bool zipFileContains(File inZip, S fileName) ctex {
  ZipFile zip = new ZipFile(inZip);
  try {
    ret zipFileContains(zip, fileName);
  } finally {
    zip.close();
  }
}
    
static bool zipFileContains(ZipFile zip, S fileName) ctex {
  ret zip.getEntry(fileName) != null;
}