Added missing @classmethod
Added missing @classmethod

lpsinger/astropy,DougBurke/astropy,joergdietrich/astropy,mhvk/astropy,dhomeier/astropy,StuartLittlefair/astropy,MSeifert04/astropy,mhvk/astropy,larrybradley/astropy,pllim/astropy,aleksandr-bakanov/astropy,astropy/astropy,saimn/astropy,joergdietrich/astropy,stargaser/astropy,saimn/astropy,larrybradley/astropy,tbabej/astropy,AustereCuriosity/astropy,joergdietrich/astropy,stargaser/astropy,AustereCuriosity/astropy,tbabej/astropy,tbabej/astropy,stargaser/astropy,MSeifert04/astropy,funbaker/astropy,dhomeier/astropy,aleksandr-bakanov/astropy,saimn/astropy,StuartLittlefair/astropy,bsipocz/astropy,pllim/astropy,astropy/astropy,StuartLittlefair/astropy,dhomeier/astropy,kelle/astropy,mhvk/astropy,saimn/astropy,saimn/astropy,astropy/astropy,DougBurke/astropy,dhomeier/astropy,astropy/astropy,funbaker/astropy,aleksandr-bakanov/astropy,bsipocz/astropy,astropy/astropy,lpsinger/astropy,AustereCuriosity/astropy,bsipocz/astropy,tbabej/astropy,DougBurke/astropy,lpsinger/astropy,larrybradley/astropy,joergdietrich/astropy,mhvk/astropy,MSeifert04/astropy,kelle/astropy,tbabej/astropy,StuartLittlefair/astropy,AustereCuriosity/astropy,AustereCuriosity/astropy,mhvk/astropy,StuartLittlefair/astropy,bsipocz/astropy,DougBurke/astropy,funbaker/astropy,lpsinger/astropy,dhomeier/astropy,kelle/astropy,pllim/astropy,larrybradley/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,lpsinger/astropy,pllim/astropy,larrybradley/astropy,kelle/astropy,kelle/astropy,pllim/astropy,stargaser/astropy,funbaker/astropy,joergdietrich/astropy