docs: def ensure_dir_exists(verify_dir):
      """Ensure directory exists. Create if necessary."""
      if not os.path.exists(verify_dir):
          # Doesn't exist create dir
          os.makedirs(verify_dir)
      else:
          # Exists
          if not os.path.isdir(verify_dir):
              # Not a dir, raise an exception
              raise ValueError("{} is not a directory".format(verify_dir))