Get an account's tokens
    Returns the list of tokens on success
    Returns None if not found

def namedb_get_account_tokens(cur, address):
    """
    Get an account's tokens
    Returns the list of tokens on success
    Returns None if not found
    """
    sql = 'SELECT DISTINCT type FROM accounts WHERE address = ?;'
    args = (address,)

    rows = namedb_query_execute(cur, sql, args)
    ret = []
    for row in rows:
        ret.append(row['type'])

    return ret