I'm not exactly sure why I'm not getting the correct.
the problem is that the function returns None.

def reverse(text):
    my_list = list(text)
    for x in range(0,len(text)) :
        new_thing1 = my_list.append(my_list.pop(0))
        new_thing = str(new_thing1)
    return new_thing


first append method does not return any value but updates existing list.

second you didn't update new_thing variable

i think you wanna pop x ( every element in the list ) not only 0 ( the first element in the list )