def UnitToValue(unit):
    """Return the value of an unit."""
    if not unit or unit.upper() in frozenset(['ECU', 'GCEU', 'HRZ']):
        return 1
    unit = unit[0].upper()
    if unit == 'K':
        return 1024
    if unit == 'M':
        return 1024 * 1024
    if unit == 'G':
        return 1024 * 1024 * 1024
    raise Exception("Not valid unit: '%s'" % unit)
