<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def validate(self, vat_deets):
 """Validates an existing VAT identification number against VIES."""

        request = self._get('validation', vat_deets)
        return self.responder(request)