Better validation in SlicedIndex.__init__
Better validation in SlicedIndex.__init__

saimn/astropy,pllim/astropy,dhomeier/astropy,StuartLittlefair/astropy,larrybradley/astropy,saimn/astropy,lpsinger/astropy,pllim/astropy,lpsinger/astropy,lpsinger/astropy,larrybradley/astropy,dhomeier/astropy,pllim/astropy,aleksandr-bakanov/astropy,aleksandr-bakanov/astropy,saimn/astropy,mhvk/astropy,saimn/astropy,astropy/astropy,lpsinger/astropy,mhvk/astropy,astropy/astropy,larrybradley/astropy,mhvk/astropy,StuartLittlefair/astropy,pllim/astropy,larrybradley/astropy,lpsinger/astropy,larrybradley/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,mhvk/astropy,astropy/astropy,dhomeier/astropy,astropy/astropy,aleksandr-bakanov/astropy,saimn/astropy,dhomeier/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,astropy/astropy,mhvk/astropy,dhomeier/astropy,pllim/astropy