For this script, we will need quite specific modules. We will be needing the maketrans feature, and the lowercase and uppercase features from the string module.

To use the ROT13 encoding method, we need to replicate what the ROT13 cipher actually does. The 13 indicates that each letter will be moved 13 places along the alphabet scale, which makes the encoding very easy to reverse:

from string import maketrans, lowercase, uppercase
def rot13(message):
   lower = maketrans(lowercase, lowercase[13:] + lowercase[:13])
   upper = maketrans(uppercase, uppercase[13:] + uppercase[:13])
   return message.translate(lower).translate...