PLEASE help me solve this with details

Examine the code below. Answer the questions that follow. alphabet="abcdefghijklmnopqrstuvwxyz" def encrypt(plaintext): ciphertext="" for i in range (, len(plaintext)): for j in range( (0, len(alphabet ) ): if plaintext [i]==alphabet [j]: ciphertext+=alphabet [(j+3)%26] print("Encrypted Message:", ciphertext) You may find it useful to run the code before attempting the questions. 1. Modify the encryption function to allow the user to enter any shift key to encrypt their message. 2. Create a function called 'decrypt' that accepts ciphertext and the shift key from the user and then decrypts the ciphertext. 3. Create a function called 'bruteforce' that will accept ciphertext from the user and perform a brute force attack to decrypt the message. Your function must use the previously created decryption function to achieve this. 4. Save your work in a single Python (.py) file: cse1202_firstname_lastname_USI_lab1.py Note: You cannot use library functions to answer these questions