I haven't seen the code yet and I can't comment much on it. I would recommend just using another wallet that generates BIP39 instead of going with a less well-known script, or just go with Electrum. No downsides there.
The Python code is extremely simple and since it is from:
https://github.com/trezor/python-mnemonici assumed (wrongly?) that it is the way Trezor wallets generate their Bip39 mnemonic:
>>>from mnemonic import Mnemonic
>>>mnemo = Mnemonic("english")
>>>words = mnemo.generate(strength=128)
>>>print(words)
Is it safe to use?
Thanks:)