Code clean-up in diff.py
Code clean-up in diff.py

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