Now, we will implement a simple function that provides data encryption using Caesar cipher.
Your task is to:

1. Check if the character is alphabetic inside the for loop of the caesar_cipher() function. Use the .isalpha() method to do it.
2. Set the value of the key variable equal to 3.
3. Call the caesar_cipher() and specify the required arguments (plaintext and key).

Note

To provide decryption, we can use the same function but with other arguments: caesar_cipher(encrypted_text, neg_key) where neg_key = - key.