def reverse(sentence):
    """ split original sentence into a list, then append elements of the old list to the new list starting from last to first. then join the list back toghether. """
    original = sentence.split()

    reverse = []

    count = len(original) - 1

    while count >= 0:
        reverse.append(original[count])
        count = count - 1

    result = " ".join(reverse)

    return result