def reify(to_reify):
    """ Reify the indicated objects.

        o If 'to_reify' is a string, treat it as an OID.

        o Otherwise, iterate over it as a sequence of OIDs.

        o For each OID, if present in 'data' and in GHOST state:

            o Call '_p_activate' on the object.

            o Add it to the ring.

        o If any OID is present but not in GHOST state, skip it.

        o Raise KeyErrory if any OID is not present.
        """
