Email (record): 5′′-(2,4-Dichloro­benzyl­idene)-1′-(2,4-dichloro­phen­yl)-1′′-methyl-1′,2′,3′,5′,6′,7′,8′,8a’-octa­hydro­dispiro­[acenaphthyl­ene-1,3′-indolizine-2′,3′′-piperidine]-2,4′′(1H)-dione