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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_vads_payment_config(self):
 """ vads_payment_config can be set only after object saving. A custom payment config can be set once PaymentRequest saved (adding elements to the m2m relationship). As a consequence we set vads_payment_config just before sending data elements to payzen."""

        self.vads_payment_config = tools.get_vads_payment_config(
            self.payment_config, self.custom_payment_config.all())