Make self.masked attribute read-only
Make self.masked attribute read-only

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