Is python is fully thread safe

[Jon Perez]

Someone please explain to me where is the wit in this...

jepler at unpythonic.net wrote:

> No.  Not all Python programs are thread safe.  For instance, here is a
> Python program that has a problem due to "threads"
> 
> 
> s = """Gur Mra bs Clguba, ol Gvz Crgref
> 
> Ornhgvshy vf orggre guna htyl.
> Rkcyvpvg vf orggre guna vzcyvpvg.
> Fvzcyr vf orggre guna pbzcyrk.
> Pbzcyrk vf orggre guna pbzcyvpngrq.
> Syng vf orggre guna arfgrq.
> Fcnefr vf orggre guna qrafr.
> Ernqnovyvgl pbhagf.
> Fcrpvny pnfrf nera'g fcrpvny rabhtu gb oernx gur ehyrf.
> Nygubhtu cenpgvpnyvgl orngf chevgl.
> Reebef fubhyq arire cnff fvyragyl.
> Hayrff rkcyvpvgyl fvyraprq.
> Va gur snpr bs nzovthvgl, ershfr gur grzcgngvba gb thrff.
> Gurer fubhyq or bar-- naq cersrenoyl bayl bar --boivbhf jnl gb qb vg.
> Nygubhtu gung jnl znl abg or boivbhf ng svefg hayrff lbh'er Qhgpu.
> Abj vf orggre guna arire.
> Nygubhtu arire vf bsgra orggre guna *evtug* abj.
> Vs gur vzcyrzragngvba vf uneq gb rkcynva, vg'f n onq vqrn.
> Vs gur vzcyrzragngvba vf rnfl gb rkcynva, vg znl or n tbbq vqrn.
> Anzrfcnprf ner bar ubaxvat terng vqrn -- yrg'f qb zber bs gubfr!"""
> 
> d = {}
> for c in (65, 97):
>     for i in range(26):
>         d[chr(i+c)] = chr((i+13) % 26 + c)
> 
> threads
> 
> print "".join([d.get(c, c) for c in s])