Oops--None should still be an allowed input as the default
Oops--None should still be an allowed input as the default

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