Generating P2WSH addresses | Is there a standard WitnessScript?
It is 0 and a 32-byte push of Sha256 of the scriptPubKey (which is the script you use to generate the address). You can find an example here: https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#p2wsh
The Python example you linked uses WP2PSH as WP2PKH. You can see the how WP2PKH works here: https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#p2wpkh