def to_us(amount, unit):
    """
    Used to convert metric (amount, unit) pairs to U.S. versions, e.g.,
    (18.9270589, 'LITER') -> (5, 'GALLON')
    """
    if unit == 'KILOGRAM':
        return (amount * 2.20462262, 'POUND')
    if unit == 'GRAM':
        return (amount * 0.0352739619, 'OUNCE')
    if unit == 'LITER':
        return (amount * 0.264172052, 'GALLON')
    return (amount, unit)