return NULL;
MP_INLINE void *modperl_hash_tied_object(pTHX_                                          const char *classname,                                         SV *tsv){    if (sv_derived_from(tsv, classname)) {        if (SVt_PVHV == SvTYPE(SvRV(tsv))) {            SV *hv = SvRV(tsv);            MAGIC *mg;            if (SvMAGICAL(hv)) {                if ((mg = mg_find(hv, PERL_MAGIC_tied))) {                    return (void *)MgObjIV(mg);                }                else {                    Perl_warn(aTHX_ "Not a tied hash: (magic=%c)", mg);                }            }            else {                Perl_warn(aTHX_ "SV is not tied");            }        }        else {            return (void *)SvObjIV(tsv);        }    }    else {        Perl_croak(aTHX_                   "argument is not a blessed reference "                   "(expecting an %s derived object)", classname);    }    return NULL;}