<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def decode_aes256_cbc_base64(data, encryption_key):
 """Decrypts base64 encoded AES-256 CBC bytes."""

    if not data:
        return b''
    else:
        # LastPass AES-256/CBC/base64 encryted string starts with an "!".
        # Next 24 bytes are the base64 encoded IV for the cipher.
        # Then comes the "|".
        # And the rest is the base64 encoded encrypted payload.
        return decode_aes256(
            'cbc',
            decode_base64(data[1:25]),
            decode_base64(data[26:]),
            encryption_key)