How to use the cryptoconditions.ThresholdSha256 function in cryptoconditions

def test_generate_outputs_split_half_single_owner(user_pub,
                                                  user2_pub, user3_pub):
    from bigchaindb.common.transaction import Output
    from cryptoconditions import Ed25519Sha256, ThresholdSha256

    expected_simple1 = Ed25519Sha256(public_key=b58decode(user_pub))
    expected_simple2 = Ed25519Sha256(public_key=b58decode(user2_pub))
    expected_simple3 = Ed25519Sha256(public_key=b58decode(user3_pub))

    expected = ThresholdSha256(threshold=2)
    expected_threshold = ThresholdSha256(threshold=2)
    expected_threshold.add_subfulfillment(expected_simple2)
    expected_threshold.add_subfulfillment(expected_simple3)
    expected.add_subfulfillment(expected_threshold)
    expected.add_subfulfillment(expected_simple1)

    cond = Output.generate([[expected_simple2, user3_pub], user_pub], 1)
    assert cond.fulfillment.to_dict() == expected.to_dict()

def test_generate_output_split_half_recursive(user_pub, user2_pub, user3_pub):
    from bigchaindb.common.transaction import Output
    from cryptoconditions import Ed25519Sha256, ThresholdSha256

    expected_simple1 = Ed25519Sha256(public_key=b58decode(user_pub))
    expected_simple2 = Ed25519Sha256(public_key=b58decode(user2_pub))
    expected_simple3 = Ed25519Sha256(public_key=b58decode(user3_pub))

    expected = ThresholdSha256(threshold=2)
    expected.add_subfulfillment(expected_simple1)
    expected_threshold = ThresholdSha256(threshold=2)
    expected_threshold.add_subfulfillment(expected_simple2)
    expected_threshold.add_subfulfillment(expected_simple3)
    expected.add_subfulfillment(expected_threshold)

    cond = Output.generate([user_pub, [user2_pub, expected_simple3]], 1)
    assert cond.fulfillment.to_dict() == expected.to_dict()

def test_validate_tx_threshold_duplicated_pk(user_pub, user_priv,
                                             asset_definition):
    from cryptoconditions import Ed25519Sha256, ThresholdSha256
    from bigchaindb.common.transaction import Input, Output, Transaction

    threshold = ThresholdSha256(threshold=2)
    threshold.add_subfulfillment(
        Ed25519Sha256(public_key=b58decode(user_pub)))
    threshold.add_subfulfillment(
        Ed25519Sha256(public_key=b58decode(user_pub)))

    threshold_input = Input(threshold, [user_pub, user_pub])
    threshold_output = Output(threshold, [user_pub, user_pub])

    tx = Transaction(Transaction.CREATE, asset_definition,
                     [threshold_input], [threshold_output])

    tx_dict = tx.to_dict()
    tx_dict['inputs'][0]['fulfillment'] = None
    serialized_tx = json.dumps(tx_dict, sort_keys=True,
                               separators=(',', ':'), ensure_ascii=True)
    message = sha3_256(serialized_tx.encode()).digest()

def test_generate_output_split_half_recursive(user_pub, user2_pub, user3_pub):
    from bigchaindb.common.transaction import Output
    from cryptoconditions import Ed25519Sha256, ThresholdSha256

    expected_simple1 = Ed25519Sha256(public_key=b58decode(user_pub))
    expected_simple2 = Ed25519Sha256(public_key=b58decode(user2_pub))
    expected_simple3 = Ed25519Sha256(public_key=b58decode(user3_pub))

    expected = ThresholdSha256(threshold=2)
    expected.add_subfulfillment(expected_simple1)
    expected_threshold = ThresholdSha256(threshold=2)
    expected_threshold.add_subfulfillment(expected_simple2)
    expected_threshold.add_subfulfillment(expected_simple3)
    expected.add_subfulfillment(expected_threshold)

    cond = Output.generate([user_pub, [user2_pub, expected_simple3]], 1)
    assert cond.fulfillment.to_dict() == expected.to_dict()

def _fulfillment_from_details(data, _depth=0):
    """Load a fulfillment for a signing spec dictionary

    Args:
        data: tx.output[].condition.details dictionary
    """
    if _depth == 100:
        raise ThresholdTooDeep()

    if data['type'] == 'ed25519-sha-256':
        public_key = base58.b58decode(data['public_key'])
        return Ed25519Sha256(public_key=public_key)

    if data['type'] == 'threshold-sha-256':
        threshold = ThresholdSha256(data['threshold'])
        for cond in data['subconditions']:
            cond = _fulfillment_from_details(cond, _depth+1)
            threshold.add_subfulfillment(cond)
        return threshold

    raise UnsupportedTypeError(data.get('type'))

if amount < 1:
            raise AmountError('`amount` needs to be greater than zero')
        if not isinstance(public_keys, list):
            raise TypeError('`public_keys` must be an instance of list')
        if len(public_keys) == 0:
            raise ValueError('`public_keys` needs to contain at least one'
                             'owner')
        elif len(public_keys) == 1 and not isinstance(public_keys[0], list):
            if isinstance(public_keys[0], Fulfillment):
                ffill = public_keys[0]
            else:
                ffill = Ed25519Sha256(
                    public_key=base58.b58decode(public_keys[0]))
            return cls(ffill, public_keys, amount=amount)
        else:
            initial_cond = ThresholdSha256(threshold=threshold)
            threshold_cond = reduce(cls._gen_condition, public_keys,
                                    initial_cond)
            return cls(threshold_cond, public_keys, amount=amount)

def _fulfillment_from_details(data, _depth=0):
    """Load a fulfillment for a signing spec dictionary

    Args:
        data: tx.output[].condition.details dictionary
    """
    if _depth == 100:
        raise ThresholdTooDeep()

    if data['type'] == 'ed25519-sha-256':
        public_key = base58.b58decode(data['public_key'])
        return Ed25519Sha256(public_key=public_key)

    if data['type'] == 'threshold-sha-256':
        threshold = ThresholdSha256(data['threshold'])
        for cond in data['subconditions']:
            cond = _fulfillment_from_details(cond, _depth+1)
            threshold.add_subfulfillment(cond)
        return threshold

    raise UnsupportedTypeError(data.get('type'))

if amount < 1:
            raise AmountError('`amount` needs to be greater than zero')
        if not isinstance(public_keys, list):
            raise TypeError('`public_keys` must be an instance of list')
        if len(public_keys) == 0:
            raise ValueError('`public_keys` needs to contain at least one'
                             'owner')
        elif len(public_keys) == 1 and not isinstance(public_keys[0], list):
            if isinstance(public_keys[0], Fulfillment):
                ffill = public_keys[0]
            else:
                ffill = Ed25519Sha256(
                    public_key=base58.b58decode(public_keys[0]))
            return cls(ffill, public_keys, amount=amount)
        else:
            initial_cond = ThresholdSha256(threshold=threshold)
            threshold_cond = reduce(cls._gen_condition, public_keys,
                                    initial_cond)
            return cls(threshold_cond, public_keys, amount=amount)

Note:
                This method works only for the following Cryptoconditions
                currently:
                    - Ed25519Fulfillment
                    - ThresholdSha256.

            Args:
                input_ (:class:`~bigchaindb.common.transaction.
                    Input`) The Input to be signed.
                message (str): The message to be signed
                key_pairs (dict): The keys to sign the Transaction with.
        """
        if isinstance(input_.fulfillment, Ed25519Sha256):
            return cls._sign_simple_signature_fulfillment(input_, message,
                                                          key_pairs)
        elif isinstance(input_.fulfillment, ThresholdSha256):
            return cls._sign_threshold_signature_fulfillment(input_, message,
                                                             key_pairs)
        else:
            raise ValueError("Fulfillment couldn't be matched to "
                             'Cryptocondition fulfillment type.')

Args:
                initial (:class:`cryptoconditions.ThresholdSha256`):
                    A Condition representing the overall root.
                new_public_keys (:obj:`list` of :obj:`str`|str): A list of new
                    owners or a single new owner.

            Returns:
                :class:`cryptoconditions.ThresholdSha256`:
        """
        try:
            threshold = len(new_public_keys)
        except TypeError:
            threshold = None

        if isinstance(new_public_keys, list) and len(new_public_keys) > 1:
            ffill = ThresholdSha256(threshold=threshold)
            reduce(cls._gen_condition, new_public_keys, ffill)
        elif isinstance(new_public_keys, list) and len(new_public_keys) <= 1:
            raise ValueError('Sublist cannot contain single owner')
        else:
            try:
                new_public_keys = new_public_keys.pop()
            except AttributeError:
                pass
            # NOTE: Instead of submitting base58 encoded addresses, a user
            #       of this class can also submit fully instantiated
            #       Cryptoconditions. In the case of casting
            #       `new_public_keys` to a Ed25519Fulfillment with the
            #       result of a `TypeError`, we're assuming that
            #       `new_public_keys` is a Cryptocondition then.
            if isinstance(new_public_keys, Fulfillment):
                ffill = new_public_keys