Python 3.xでCodeEvalのRoller Coaster

アルファベットを１文字ずつ大文字、小文字にして出力する。
ピリオドやカンマなどはそのまま出力する。

input

To be, or not to be: that is the question.
Whether 'tis nobler in the mind to suffer
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles,
And by opposing end them? To die: to sleep.

output

To Be, Or NoT tO bE: tHaT iS tHe QuEsTiOn.
WhEtHeR 'tIs NoBlEr In ThE mInD tO sUfFeR
ThE sLiNgS aNd ArRoWs Of OuTrAgEoUs FoRtUnE,
Or To TaKe ArMs AgAiNsT a SeA oF tRoUbLeS,
AnD bY oPpOsInG eNd ThEm? To DiE: tO sLeEp.