Sure, below there's the DECLARE model expressed in Python dict format considering common constraints found on typical Purchase-to-Pay processes:


```python
pm4py_model = {
    'existence': {'create_order': {},
                   'process_invoice': {}},
    
    'absence': {'cancel_order': {}, 
                'add_product_to_order': {},},
    
    'exactly_one': {'order_payment': {},  
                    'create_order': {'order_payment'}},
    
    'init': {'create_order': {},},
    
    'responded_existence': {
        ('create_order', 'order_invoice'): {},
        ('order_payment', 'register_payment'): {},
    },
    
    'coexistence': {
        ('add_product_to_order', 'process_invoice'): {},      
    },
    
    'response': {
        ('add_product_to_order', 'create_order'): {},
        ('create_order', 'order_payment'): {},
        ('order_invoice', 'update_inventory_status'): {},
    },
    
    'precedence': {'cancel_order': {'order_payment'}},
    
    'succession': {'order_payment': {'register_payment'}, 
                  ('add_product_to_order', 'process_invoice'): {},},
    
    'altresponse': {
        ('create_order', 'order_payment'): {}},        
                    
    'chainresponse': {
        ('add_product_to_order', 'process_invoice', 'register_payment'): {}}
}

# Here are some additional rules specific for non coexistence, succession and chain succession

    'noncoexistence': {'(create_order, process_invoice)': {},},
    
    'nonsuccession': {'(order_payment)',{}},
    
    'nonchainsuccession': {
        ('add_product_to_order', 'process_invoice', 'register_payment'): {},}
}  

# We can then add the remaining (if not already declared):

    # Declarative constraints for 'absence' and 'exactly_one'
    'absence': {'(cancel_order)', {}},
    
    'exactly_one': {'order_payment': {}},}

# The model is completed with the same structure applied recursively for the remaining activities in Purchase-to-Pay process flowchart
```

In this hypothetical example, the process flow is simplified to demonstrate the declarative model creation using DECLARE semantics based on given examples.

Each key within a dictionary represents different semantic relationships between the entities (activities) involved within an organizational process:

`'existence', 'absence', 'exactly_one', 'init'`: These constraints are fundamental for any activity in this process stating that these activities must exist (`'existence'`) or not exist (`'absence'`) once (`'exactly_one'`) and the sequence (`'init'`).

`'responded_existence', 'coexistence'`: These represent relationships where if one activity is executed (`'responded_existence'`, `'coexistence'`) another must follow immediately.

`'response', 'precedence', 'succession'`: These are similar but with different semantic meaning regarding the execution order (`'response'`, `'precedence'`, `succession'`). 

`'altresponse', 'chainresponse'`: Represent the cases when activities in the chain must happen alternatively (`'altresponse'`) without repetitions (`'chainresponse'`).

`'noncoexistence', 'nonsuccession', 'nonchainsuccession'`: These represent exceptions where certain activities must not be executed together (`'noncoexistence'`), cannot have a specific order (`'nonsuccession'`), or can't follow each other (`'nonchainsuccession'`).

Remember that the complete model would need comprehensive process definition based on the actual flowchart of Purchase-to-Pay process tasks, conditions for starting activities (`'init'`) and relationships among them (`'responded_existence', 'coexistence', 'response', 'precedence', 'succession'`). The given rules here are simplified examples demonstrating how these keys could be used within a model created with the DECLARE semantics framework