How to implement

_description

Customer's can purchase things, and employees can be paid a commission for assisting the customer in their purchase.  What methods would you create to do this?

onCustomer.py

class Employee:

    name = None

    def getCommission(self, product):
        if product == 'apple':
            return 1.0
        else:
            return 0.5


class Customer:

    name = None
    
    
    def purchase(self, product, amount):
        p = Purchase()
        p.product = product
        p.amount = amount
        p.customer = self
        return p


    def employee_assisted_purchase(self, employee, *a, **kw):
        p = self.purchase(*a, **kw)
        c = Commission()
        c.employee = employee
        c.purchase = p
        c.amount = employee.getCommission(p.product)
        return p


class Purchase:

    name = None
    customer = None
    amount = None


class Commission:

    purchase = None
    employee = None
    amount = None

onEmployee.py

class Employee:

    name = None

    def getCommission(self, product):
        if product == 'apple':
            return 1.0
        else:
            return 0.5

    def customer_purchase(self, customer, *a, **kw):
        p = customer.purchase(*a, **kw)
        c = Commission()
        c.employee = self
        c.purchase = p
        c.amount = self.getCommission(p.product)
        return p


class Customer:

    name = None
    
    
    def purchase(self, product, amount):
        p = Purchase()
        p.product = product
        p.amount = amount
        p.customer = self
        return p


class Purchase:

    name = None
    customer = None
    amount = None


class Commission:

    purchase = None
    employee = None
    amount = None