I don’t know why you still need to use chr and ord?? What I mean is: your requirement is very simple. You already know the 26 letters, but you are wrong by 2 digits.

>>> from string import ascii_lowercase as keys
>>> vals = keys[2:] + keys[:2]
>>> dict(zip(keys, vals))
{'a': 'c', 'c': 'e', 'b': 'd', 'e': 'g', 'd': 'f', 'g': 'i', 'f': 'h', 'i': 'k', 'h': 'j', 'k': 'm', 'j': 'l', 'm': 'o', 'l': 'n', 'o': 'q', 'n': 'p', 'q': 's', 'p': 'r', 's': 'u', 'r': 't', 'u': 'w', 't': 'v', 'w': 'y', 'v': 'x', 'y': 'a', 'x': 'z', 'z': 'b'}

The requirement has been fulfilled. I think the key to your question may not be what I answered.

from string import maketrans 
int = "abcdefghijklmnopqrstuvwxyz"
out = "cdefghijklmnopqrstuvwxyzab"

b = "g fmnc wms bgblr rpylqjyrc gr zw fylb. rfyrq ufyr amknsrcpq ypc dmp. bmgle gr gl zw fylb gq glcddgagclr ylb rfyr'q ufw rfgq rcvr gq qm jmle. sqgle qrpgle.kyicrpylq() gq pcamkkclbcb. lmu ynnjw ml rfc spj."

trans_int_out = maketrans(int, out)
print b.translate(trans_int_out)

Python Challenge Level 1 Walkthrough

dict(zip(al, map(lambda x : chr((ord(x) - 95) % 26 + 97), al)) )

Sit back and wait for the master...

a = 'abcdefghijklmnopqrstuvwxyz'
b = [chr(((ord(x) - 95) % 26) + 97) for x in a]
>>> b
['c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b']

Haha, there is no inspection part

from string import ascii_lowercase
from itertools import cycle
from itertools import islice
from itertools import izip

N = 2

dict(izip(ascii_lowercase,
          islice(cycle(ascii_lowercase),
                 N,
                 None)))

Not Pythonic at all :(