Change each character in string to the next character in alphabet

Question

I am coding in Python 2.7 using PyCharm on Ubuntu.

I am trying to create a function that will take a string and change each character to the character that would be

Answer 1

this is my code i think it is very simple

def LetterChanges(st):
    index = 0
    new_word = ""
    alphapet = "abcdefghijklmnopqrstuvwxyzacd"

    for i in st.lower():
        if i.islower(): #check if i s letter
            index = alphapet.index(i) + 1 #get the index of the following letter
            new_word += alphapet[index]    
        else: #if not letter
            new_word += i    
    return new_word


print LetterChanges(raw_input())