add user input to list

add user input to list

I want it to ask the user to input their favorite film and it to add that
input at the end of the list and then display the list again. as well as
making sure the film entered is not in the least already. this is how far
ive got up to :
films = ["Star Wars", "Lord of the Rings", "Shawshank Redemption", "God
father"]
for films in films:
print ("%s" % films)
add = input("Please enter a film: ")
films.insert(-1,add)
print (films)
Edit:
When I tried that I get an error:
Traceback (most recent call last):
File "H:\Modules (Year 2)\Advanced programming\Python\Week 2 - Review and
Arrays\Week 2.2 - Exercises.py", line 48, in films.append(add)
AttributeError: 'str' object has no attribute 'append'