Allocate method coupled with OrderLine vs decoupled

coupled_allocate_service.py

# SERVICE LAYER
# we have to send an OrderLine to the domain service allocate, thus still coupled
def allocate(orderid:str, sku: str, qty: int, repo: AbstractRepository, session) -> str:
    """
    Obtains a list of Batches from data layer, validates OrderLine,
    calls the allocate domain service, and commits to database.
    """
    batches = repo.list()
    if not is_valid_sku(sku, batches):
        raise InvalidSKU(f'Invalid SKU: {sku}')
    line = model.OrderLine(orderid, sku, qty)
    ref = model.allocate(line, batches)
    session.commit()
    return ref

decoupled_allocate_service.py

# SERVICE LAYER
# we no longer need an OrderLine, just pass the primitives and let domain service handle it
def allocate(orderid:str, sku: str, qty: int, repo: AbstractRepository, session) -> str:
    """
    Obtains a list of Batches from data layer, validates OrderLine,
    calls the allocate domain service, and commits to database.
    """
    batches = repo.list()
    if not is_valid_sku(sku, batches):
        raise InvalidSKU(f'Invalid SKU: {sku}')
    ref = model.allocate(orderid, sku, qty, batches)
    session.commit()
    return ref

domain_allocate_expects_order_line.py.py

# DOMAIN LAYER
# domain service expects OrderLine 
def allocate(line: OrderLine, batches: List[Batch]) -> str:
    """
    Domain Service to allocate order lines against a list of batches
    """
    assert len(batches) > 0, "At least 1 batch is needed"
    try:
        batch = next(
            b for b in sorted(batches)
            if b.can_allocate(line)
        )
        batch.allocate(line)
        return batch.ref
    except StopIteration:
        raise OutOfStock(f'Out of stock for {line.sku}')

domain_allocate_expects_primitives.py

# DOMAIN LAYER
# domain service expects primitives instead and handles building Orderline within
def allocate(orderid: OrderId, sku: Sku, qty: Qty, batches: List[Batch]) -> str:
    """
    Domain Service to allocate order lines against a list of batches
    """
    assert len(batches) > 0, "At least 1 batch is needed"
    line = OrderLine(orderid, sku, qty)
    try:
        batch = next(
            b for b in sorted(batches)
            if b.can_allocate(line)
        )
        batch.allocate(line)
        return batch.ref
    except StopIteration:
        raise OutOfStock(f'Out of stock for {line.sku}')