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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_unit_price(self, value):
        '''
        Sets the unit price
        @param value:str
        '''
        try:
            if value < 0:
                raise ValueError()

            self.__unit_price = Decimal(str(value))
        except ValueError:
            raise ValueError("Unit Price must be a positive number")