I was making a simple Caesarian cipher when this issue came up.

#Following code here

>>> import string
>>> CAESER_SHIFT = 13
>>> TranslationTableUpper = [string.ascii_uppercase[(index +
CAESER_SHIFT) % 26] for index in range(26)]
>>> TranslationTableLower = [string.ascii_lowercase[(index +
CAESER_SHIFT) % 26] for index in range(26)]
>>> TranslationTableCipher = ''.join(TranslationTableUpper +
TranslationTableLower)
>>> TranslationTableRegular = string.ascii_uppercase[0:27] +
string.ascii_lowercase[0:27]
>>> Trans = ''.maketrans(TranslationTableCipher, TranslationTableRegular)
>>> print(Trans)
{65: 78, 66: 79, 67: 80, 68: 81, 69: 82, 70: 83, 71: 84, 72: 85, 73: 86,
74: 87, 75: 88, 76: 89, 77: 90, 78: 65, 79: 66, 80: 67, 81: 68, 82: 69,
83: 70, 84: 71, 85: 72, 86: 73, 87: 74, 88: 75, 89: 76, 90: 77, 97: 110,
98: 111, 99: 112, 100: 113, 101: 114, 102: 115, 103: 116, 104: 117, 105:
118, 106: 119, 107: 120, 108: 121, 109: 122, 110: 97, 111: 98, 112: 99,
113: 100, 114: 101, 115: 102, 116: 103, 117: 104, 118: 105, 119: 106,
120: 107, 121: 108, 122: 109}
>>> #Okay... so maketrans() is working okay when calling it on an empty
string, buuuut if called from the string module...
>>> Trans = string.maketrans(TranslationTableCipher,
TranslationTableRegular)
    Trans = string.maketrans(TranslationTableCipher,
TranslationTableRegular)
  File "D:\Python31\lib\string.py", line 55, in maketrans
    raise TypeError("maketrans arguments must be bytes objects")
TypeError: maketrans arguments must be bytes objects

This seems to have been intentional. I'm assigning it to Georg since he
made the commit.

This is (kind of) intentional.  string.maketrans operates on bytes, not
string objects.  However, this is quite confusing, so I added
bytes.maketrans() now in py3k, and deprecated string.maketrans(). (r71521)

The bytearray.maketrans() method isn't documented yet.

Should be fixed in r73086.