check to see if target unit is a string, if so, assume it is a physical type
check to see if target unit is a string, if so, assume it is a physical type

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