data = response.json()
        if "Error Message" in data:
            raise ValueError(f"API Error: {data['Error Message']}")
        return data
    @property
    def standard_currencies(self) -> List[str]:
        return ["USD", "EUR", "GBP", "JPY", "CHF", "CAD", "AUD", "NZD"]
[docs]    def run(self, from_currency: str, to_currency: str) -> str:
        """Get the current exchange rate for a specified currency pair."""
        if to_currency not in self.standard_currencies:
            from_currency, to_currency = to_currency, from_currency
        data = self._get_exchange_rate(from_currency, to_currency)
        return data["Realtime Currency Exchange Rate"]