EXCHANGE_RATE

=EXCHANGE_RATE(base_currency, target_currency)

=EXCHANGE_RATE("USD", "SGD")

=EXCHANGE_RATE("EUR", "USD")

import requests
 
def exchange_rate(base_currency, target_currency):
    """
    Retrieves the exchange rate from a base currency to a target currency using a public API.
 
    Args:
        base_currency: The base currency code (e.g., "USD").
        target_currency: The target currency code (e.g., "SGD").
 
    Returns:
        The exchange rate as a float, or an error message as a string if the input or API call fails.
 
    This example function is provided as-is without any representation of accuracy.
    """
    if not (isinstance(base_currency, str) and isinstance(target_currency, str)):
        return "Error: Both base_currency and target_currency must be strings."
    url = f"https://api.exchangerate-api.com/v4/latest/{base_currency}"
    try:
        response = requests.get(url)
        if response.status_code == 200:
            data = response.json()
            if target_currency in data.get('rates', {}):
                return data['rates'][target_currency]
            else:
                return f"Error: Target currency '{target_currency}' not found in API response. See https://www.exchangerate-api.com/docs/supported-currencies."
        else:
            return f"Error: HTTP {response.status_code} when fetching exchange rates."
    except Exception as e:
        return f"Error: {str(e)}"