Bip39 buffer is not defined https://squareblogs.net/edelinepge/using-python-to-produce-a-bip39-mnemonic-a-developers-point-of-view It is very important that the mnemonic sentences are generated from randomly chosen quantities! These quantities could be created in a variety of alternative ways, which are explained in other posts in this article, like "What's an RNG" and Seed Phrase Gen... https://funny-lists.com/story21317805/bip39-passphrase-empty-for-none-bip39-github-an-overview-https-dzen-ru-bip39-phrase-com