Module types 

Data types for API responses and requests

Structs

ApiErrorResponse

Error response from the API

ConversionResponse

Response for a specific currency pair conversion

ExchangeRateResponse

Response from the exchange rate API for latest rates

HistoricalConversionRequest

Historical conversion request

HistoricalRateResponse

Response for historical exchange rates

SupportedCurrenciesResponse

Supported currencies response

Constants

COMMON_CURRENCIES

Common currency codes for validation and suggestions

Functions

is_common_currency

Check if a currency code is commonly used

is_valid_currency_code

Validation for currency codes (ISO 4217 format)

is_valid_date_format

Validate date format (YYYY-MM-DD)