 Sure, here is a hypothetical DECLARE model for a Purchase-to-Pay process:

```python
declare_model = {
    'existence': {
        'Create Purchase Order': {'support': 1.0, 'confidence': 1.0},
        'Receive Goods': {'support': 1.0, 'confidence': 1.0},
        'Create Invoice': {'support': 1.0, 'confidence': 1.0},
        'Payment': {'support': 1.0, 'confidence': 1.0}
    },
    'absence': {
        'Create Purchase Order': {'support': 1.0, 'confidence': 1.0}  # This activity should not be executed more than once
    },
    'exactly_one': {
        'Payment': {'support': 1.0, 'confidence': 1.0}  # Payment should be done exactly once
    },
    'init': {
        'Create Purchase Order': {'support': 1.0, 'confidence': 1.0}  # The process starts with the creation of a Purchase Order
    },
    'responded_existence': {
        ('Create Purchase Order', 'Receive Goods'): {'support': 1.0, 'confidence': 1.0},  # If a Purchase Order is created, goods should be received
        ('Receive Goods', 'Create Invoice'): {'support': 1.0, 'confidence': 1.0},  # If goods are received, an invoice should be created
        ('Create Invoice', 'Payment'): {'support': 1.0, 'confidence': 1.0}  # If an invoice is created, a payment should be done
    },
    'coexistence': {
        ('Create Purchase Order', 'Receive Goods'): {'support': 1.0, 'confidence': 1.0},  # If a Purchase Order is created, goods should be received
        ('Receive Goods', 'Create Invoice'): {'support': 1.0, 'confidence': 1.0}  # If goods are received, an invoice should