usage: export_signing_key [-h] [-x] [--expiry-ts EXPIRY_TS] key_file [key_file ...]

positional arguments:
  key_file              The key file to read

options:
  -h, --help            show this help message and exit
  -x                    format the output for inclusion in the old_signing_keys config setting
  --expiry-ts EXPIRY_TS
                        The expiry time to use for -x, in milliseconds since 1970. The default is
                        (now+6h).