Working toward a vote for download System for Steemfiles.com

Over on Steemfiles.com you can pay for downloads. What if you could get a downloaded thing for voting for it? That's the idea of my latest contest. You can download a band performance by voting that post up. Today, I wrote source code for determining who gets the file.
The author will be compensated for every download. The script decides which user wins the download. There is more back-end work and a couple of hard coded values to remove.
Here it is:

    #!/usr/local/bin/python3.6
    # Gives a list of winners
    import hashlib
    from getpass import getpass
    from steem.steem import Steem
    import sys
    from optparse import OptionParser
    import steembase
    
    parser = OptionParser()
    parser.add_option('-l', '--permlink')
    parser.add_option('-a','--author')
    (options, args) = parser.parse_args()
    
    post_author = 'steemfiles'
    if options.permlink is not None:
        post_permlink = options.permlink
    
    if options.author is not None:
        post_author = options.author
    
    secret = getpass(prompt='Enter the secret text: ', stream=None)
    
    steem = Steem()
    # verify the user voted on the post
    try:
        active_votes = steem.get_active_votes(post_author, post_permlink)
    except steembase.exceptions.RPCError as rpce:
        print("Invalid permlink/author combination")
        sys.exit(1)
    
    def get_txid(vote_row):
        vote_time = vote_row['time']
        txs = steem.get_account_history(vote_row['voter'], index_from=999999999999999999, limit=0)
        tx = txs[0][1]
        high_value = txs[0][0]
        low_value = 1
        pivot_value = high_value # int((high_value + low_value)/2)
        while tx['timestamp'] != vote_time and high_value - low_value > 100:
            if tx['timestamp'] > vote_time:
                high_value = pivot_value
            else:
                low_value  = pivot_value
            pivot_value = int((high_value + low_value)/2)
            tx = steem.get_account_history(vote_row['voter'], index_from=pivot_value, limit=0)[0][1]
        
        # switch to a linear search as we are pretty close already and this way we do not make so many RPC calls.
        txs = steem.get_account_history(vote_row['voter'], index_from=high_value, limit=100)
        for index,tx in txs:
            if tx['timestamp'] == vote_time and tx['op'][0] == 'vote':
                vote = tx['op'][1]
                if vote['voter'] == vote_row['voter'] and vote['author'] == post_author and vote['permlink'] == post_permlink:
                    return tx['trx_id']
        else:
            assert(False)
    
    def get_number_of_winners(author, permlink):
        p = steem.get_content(author, permlink)
        return float(p['total_payout_value'].split(' ')[0])/0.002
    
        
    
    score_values = []
    for vote_bc_row in active_votes:
        try:
            m = hashlib.sha256()
            m.update((secret + ':' + get_txid(vote_bc_row)).encode('ascii'))
            digest_string = m.hexdigest()         
            score = int(vote_bc_row['rshares']) * int(vote_bc_row['percent']) * int(vote_bc_row['weight']) * 1e59 / int(digest_string, base=16)
            score_values += [[score, vote_bc_row['voter']]]
        except KeyError as e:
            print("No key ", e.args[0], " in ", vote_bc_row)
            sys.exit(0)
    
    score_values.sort()
    winner_count = get_number_of_winners(post_author, post_permlink)
    
    if winner_count > len(score_values):
        print("Everybody wins!")
        winner_count = len(score_values)
    
    print(score_values)
    if winner_count == 0:
        print("There are no winners.")
        sys.exit(0)
    
    try:
        print("winner list")
        for i in range(len(score_values)-winner_count, len(score_values)):
            print(score_values[i][1])
    except TypeError:
        print("Score values: ", score_values)