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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 add_appt(self, complex: str, house: str, price: str, square: str, **kwargs):
 """ Add a new appartment to the rumetr db """

        self.check_house(complex, house)

        kwargs['price'] = self._format_decimal(price)
        kwargs['square'] = self._format_decimal(square)

        self.post('developers/{developer}/complexes/{complex}/houses/{house}/appts/'.format(
            developer=self.developer,
            complex=complex,
            house=house,
        ), data=kwargs)