Why does "DONE" print with the list when doing this problem within a function?

print("What do you need at Wal-Mart today?")
print("Type 'DONE' when you're finished.")
slist = []

def shopping_list():
  while(True):
    userinput = input(" >> ")
    slist.append(userinput)
    if userinput == "DONE":
      print ("We are done. Here is the list of things you need.")
      #del slist[-1]
      break
  for item in slist:
      print (item)

shopping_list()

In function result:
Water
Bananas
Pencils
DONE

Without function result:
Water
Bananas
Pencils

This is the code that I created before watching Kenneth Love making his own. When running it, I noticed that DONE prints with my list. Naturally, I looked back at some notes and used the del fx [-1] to fix it. However, I'm confused because in the video, Kenneth does not use Del. When I take my Del out, unlike him, my list prints out A, B, C, etc., DONE. So, I took out 'def shopping_list(): and shopping_list()' because I noticed he never did all this inside a function. I ran it again and it now prints out the list without "DONE". Why does it print "DONE" and require a Del with the list if it's in a function?