How to use the num2words.currency.prefix_currency function in num2words

Returns:
            str: Formatted string

        """
        left, right, is_negative = parse_currency_parts(val)

        try:
            cr1, cr2 = self.CURRENCY_FORMS[currency]

        except KeyError:
            raise NotImplementedError(
                'Currency code "%s" not implemented for "%s"' %
                (currency, self.__class__.__name__))

        if adjective and currency in self.CURRENCY_ADJECTIVES:
            cr1 = prefix_currency(
                self.CURRENCY_ADJECTIVES[currency],
                cr1
            )

        minus_str = "%s " % self.negword if is_negative else ""
        cents_str = self._cents_verbose(right, currency) \
            if cents else self._cents_terse(right, currency)

        return u'%s%s %s%s %s %s' % (
            minus_str,
            self.to_cardinal(left, feminine=cr1[-1]),
            self.pluralize(left, cr1),
            separator,
            cents_str,
            self.pluralize(right, cr2)
        )

Returns:
            str: Formatted string

        """
        left, right, is_negative = parse_currency_parts(val)

        try:
            cr1, cr2 = self.CURRENCY_FORMS[currency]

        except KeyError:
            raise NotImplementedError(
                'Currency code "%s" not implemented for "%s"' %
                (currency, self.__class__.__name__))

        if adjective and currency in self.CURRENCY_ADJECTIVES:
            cr1 = prefix_currency(self.CURRENCY_ADJECTIVES[currency], cr1)

        minus_str = "%s " % self.negword if is_negative else ""
        cents_str = self._cents_verbose(right, currency) \
            if cents else self._cents_terse(right, currency)

        return u'%s%s %s%s %s %s' % (
            minus_str,
            self.to_cardinal(left),
            self.pluralize(left, cr1),
            separator,
            cents_str,
            self.pluralize(right, cr2)
        )

def to_currency(self, val, currency="JPY", cents=False, separator="",
                    adjective=False, reading=False, prefer=None):
        left, right, is_negative = parse_currency_parts(
            val, is_int_with_cents=cents)

        try:
            cr1, cr2 = self.CURRENCY_FORMS[currency]
            if (cents or abs(val) != left) and not cr2:
                raise ValueError('Decimals not supported for "%s"' % currency)
        except KeyError:
            raise NotImplementedError(
                'Currency code "%s" not implemented for "%s"' %
                (currency, self.__class__.__name__))

        if adjective and currency in self.CURRENCY_ADJECTIVES:
            cr1 = prefix_currency(self.CURRENCY_ADJECTIVES[currency], cr1)

        minus_str = self.negword if is_negative else ""

        return '%s%s%s%s%s' % (
            minus_str,
            self.to_cardinal(left, reading=reading, prefer=prefer),
            cr1[1] if reading else cr1[0],
            self.to_cardinal(right, reading=reading, prefer=prefer)
            if cr2 else '',
            (cr2[1] if reading else cr2[0]) if cr2 else '',
        )