end-to-end encryption1.py

def is_even(number):
    return number % 2 == 0

def get_even_letters(message):
    even_letters = []
    for counter in range(0, len(message)):
        if is_even(counter):
            even_letters.append(message[counter])
    return even_letters

def get_odd_letters(message):
    odd_letters = []
    for counter in range(0, len(message)):
        if not is_even(counter):
            odd_letters.append(message[counter])
    return odd_letters

What is the purpose of these functions, to find out the letters on the even positions?

What is stored in odd_letters and even_letters if the message was 'Hello world'