'Coerce some inbound object to be appropriately usable in this object
:param inbound: string or None or list or UnspacedList
:returns: (coerced UnspacedList or string or None, spaced equivalent)
:rtype: tuple'

def _coerce(self, inbound):

    if (not isinstance(inbound, list)):
        return (inbound, inbound)
    else:
        if (not hasattr(inbound, 'spaced')):
            inbound = UnspacedList(inbound)
        return (inbound, inbound.spaced)
