import re


def _split_units(lis):
    """Return the unit name if it has a value associated."""
    units = ['RPM', '%', ' V', ' C', 'Seconds',
             'Times', 'MHz', 'KB', 'MB', 'GB']
    for unit in units:
        match = re.search("(.*)%s$" % unit, lis[1])
        if match:
            lis[1] = match.group(1).replace(' ', '')
            return unit.replace(' ', '')
    return None