Sure, here's an example on how you could create a POWL model using the `pm4py` library for a hypothetical Purchase-to-Pay process. Let's assume this process involves the following activities: Purchase Requisition, Purchase Order, Goods Receipt, Invoice Receipt, and Payment.

```python
import pm4py
from pm4py.objects.powl.obj import StrictPartialOrder, OperatorPOWL, Transition, SilentTransition
from pm4py.objects.process_tree.obj import Operator

# Define activities
pr = Transition(label='Purchase Requisition')
po = Transition(label='Purchase Order')
gr = Transition(label='Goods Receipt')
ir = Transition(label='Invoice Receipt')
pay = Transition(label='Payment')
skip = SilentTransition()

# Define the process flow
# A purchase requisition is needed before issuing a purchase order
# A goods receipt is needed before an invoice receipt
xor_gr_ir = OperatorPOWL(operator=Operator.XOR, children=[gr, ir])
xor_pay_skip = OperatorPOWL(operator=Operator.XOR, children=[pay, skip])

order_pr_po = StrictPartialOrder(nodes=[pr, po])
order_po_xor_gr_ir = StrictPartialOrder(nodes=[po, xor_gr_ir])
order_xor_gr_ir_xor_pay_skip = StrictPartialOrder(nodes=[xor_gr_ir, xor_pay_skip])

# Order the defined processes
order_pr_po.order.add_edge(pr, po)
order_po_xor_gr_ir.order.add_edge(po, xor_gr_ir)
order_xor_gr_ir_xor_pay_skip.order.add_edge(xor_gr_ir, xor_pay_skip)

# Define the main POWL model
p2p_model = StrictPartialOrder(nodes=[order_pr_po, order_po_xor_gr_ir, order_xor_gr_ir_xor_pay_skip])

# The connections between sub-models 
# Purchase Requisition (PR) -> Purchase Order (PO) -> XOR(Goods Receipt (GR), Invoice Receipt (IR)) -> XOR(Payment (PAY), silent transition)
p2p_model.order.add_edge(order_pr_po, order_po_xor_gr_ir)
p2p_model.order.add_edge(order_po_xor_gr_ir, order_xor_gr_ir_xor_pay_skip)
```

This will create a POWL model where the process proceeds through stages with certain logical order. The Goods Receipt or Invoice Receipt can be next step after Purchase Order. Similarly, either Payment or a silent transition can follow after either Goods Receipt or Invoice Receipt. A silent transition is usually additioned in XOR operator to indicate that "no activity" may also be an option in this decision,