In these examples, the convertToDollar function takes two arguments - the amount to be converted and the currency in which the amount is denominated. The function then uses a predefined exchange rate to convert the amount to its equivalent value in US dollars. The package library that might contain the convertToDollar function could be a financial library, such as the Financial library in the Pear package. However, since this function is relatively simple, it could also be included in a custom application without the need for an external package.