bip39 converting from entropy to seed failing tests with entropy "00000000000000000000000000000000"
you need to remove python binary denominator '0b' and then zero fill the binary representation of sha256 digest to 256bits --> then it works



checksum = bin(sha256_entropy_int)[2:].zfill(256)[:checksum_bit_length]


also there is a reference implementation mentioned in the bip (must have missed it initially)