will convert the amount in CZK into given currency (target)
    you can calculate with regard to (given) date
    you can add additional margin with percent parameter
    valid_days_max: see rate()

def convert_to(target, amount, date=None, percent=0, valid_days_max=None):
    """will convert the amount in CZK into given currency (target)
    you can calculate with regard to (given) date
    you can add additional margin with percent parameter
    valid_days_max: see rate()
    """
    if target.upper() == 'CZK':
        result = amount
    else:
        result = amount / rate(target, date, valid_days_max=valid_days_max)
    return modified(result, percent)