code: def format_pgp_key(key):
      
      if key is None:
          return None
      if isinstance(key, (int, long)):
          return '%016x' % key
      elif isinstance(key, list):
          return [format_pgp_key(x) for x in key]
      else:
          key = key.strip()
          key = strip_hex_prefix(key)
          return format_pgp_key(int(key, 16))
docs: Formats PGP key in 16hex digits
      :param key:
      :return: