decode vote init tx op_return protobuf message and validate it.

def parse_vote_info(protobuf: bytes) -> dict:
    '''decode vote init tx op_return protobuf message and validate it.'''

    vote = pavoteproto.Vote()
    vote.ParseFromString(protobuf)

    assert vote.version > 0, {"error": "Vote info incomplete, version can't be 0."}
    assert vote.start_block < vote.end_block, {"error": "vote can't end in the past."}

    return {
        "version": vote.version,
        "description": vote.description,
        "count_mode": vote.MODE.Name(vote.count_mode),
        "choices": vote.choices,
        "start_block": vote.start_block,
        "end_block": vote.end_block,
        "vote_metainfo": vote.vote_metainfo
    }