Problem: In the book "Hands-on cryptography with Python", the authors describe the ROT13 cipher. In the author's words, ROT13 works as follows. "If you run one cycle of ROT13, it changes CELLO to PRYYB, and if you encrypt it again with the same process, putting in that PRYYB, it'll turn back into CELLO." Answer the following questions for the ROT13 cipher.
a. With screenshots, show the working (both encryption and decryption) of the ROT13 cipher with your last name as the input.
b. How would you convert the code to change it to a ROT-15 cipher? Test if your code works with your suggested changes. Provide screenshots.
c. Where has the ROT13 been used?