def METHOD_NAME(tx_result: dict, hlc_timestamp: str, rewards: list, members: list = None, members_list_hash: str = None, num_of_members: int = None) -> str:
    tx_result_hash = tx_result_hash_from_tx_result_object(
        tx_result=tx_result,
        hlc_timestamp=hlc_timestamp,
        rewards=rewards
    )
    if members is not None:
        members_list_hash = hash_members_list(members=members)
        num_of_members = len(members)
    message = tx_result_hash + members_list_hash + str(num_of_members)
    return {
        'message': message,
        'members_list_hash': members_list_hash,
        'num_of_members': num_of_members,
    }