Bip39 Checksum. Entropy values have to be sourced from a solid supply of randomness. This means flipping a fair coin, rolling a fair dice, noise measurements etc. Don't use phrases from guides, lyrics from music, your birthday or steet tackle, keyboard mashing, or just about anything you believe is random, https://directorylandia.com/listings581004/bip39-python-https-linktr-ee-bip39-a-simple-key-for-bip39-github-unveiled