def get_intermediate(self, ciphertext) -> bytes:
    key = b''
    blocks = (len(ciphertext) // self.blocksize)
    for i in range(blocks):
        block_start = (len(ciphertext) - ((i + 1) * self.blocksize))
        block_end = (len(ciphertext) - (i * self.blocksize))
        key = (self.decrypt_block(ciphertext[block_start:block_end]) + key)
    return key
def get_intermediate(self, ciphertext) -> bytes:
    key = b
    blocks = (len(ciphertext) // self.blocksize)
    for i in range(blocks):
        block_start = (len(ciphertext) - ((i + 1) * self.blocksize))
        block_end = (len(ciphertext) - (i * self.blocksize))
        key = (self.decrypt_block(ciphertext[block_start:block_end]) + key)
    return key