Converts a given amount of currency to the equivalent number of
    satoshi. The amount can be either an int, float, or string as long as
    it is a valid input to :py:class:`decimal.Decimal`.

    :param amount: The quantity of currency.
    :param currency: One of the :ref:`supported currencies`.
    :type currency: ``str``
    :rtype: ``int``

def currency_to_satoshi(amount, currency):
    """Converts a given amount of currency to the equivalent number of
    satoshi. The amount can be either an int, float, or string as long as
    it is a valid input to :py:class:`decimal.Decimal`.

    :param amount: The quantity of currency.
    :param currency: One of the :ref:`supported currencies`.
    :type currency: ``str``
    :rtype: ``int``
    """
    satoshis = EXCHANGE_RATES[currency]()
    return int(satoshis * Decimal(amount))