alguem consegue interpretar esse codigo em python e como usar?

[code=python]universe = [c for c in (chr(i) for i in range(32,127))]

uni_len = len(universe)

def vign(txt='', key='', typ='d'):
if not txt:
print ('Needs text.')
return
if not key:
print ('Needs key.')
return
if typ not in ('d', 'e'):
print ('Type must be "d" or "e".')
return
if any(t not in universe for t in key):
print ('Invalid characters in the key. Must only use ASCII symbols.')
return

ret_txt = ''
k_len = len(key)

for i, l in enumerate(txt):
if l not in universe:
ret_txt += l
else:
txt_idx = universe.index(l)

k = key[i % k_len]
key_idx = universe.index(k)
if typ == 'd':
key_idx *= -1

code = universe[(txt_idx + key_idx) % uni_len]

ret_txt += code

print (ret_txt)
return ret_txt[/code]