While loop goes on forever despite condition being met

My while loop is supposed to end once each letter in display is not an underscore.

However despite display updating to remove all underscores. The loop keeps going on, and I can’t figure out why.

import random
word_list = ["aardvark", "baboon", "camel"]
chosen_word = random.choice(word_list)
word_length = len(chosen_word)


print(f'Pssst, the solution is {chosen_word}.')

display = []
for _ in range(word_length):
    display += "_"


guess = input("Guess a letter: ").lower()

def check_letter():
  for position in range(word_length):
      letter = chosen_word[position]
      if letter == guess:
          display[position] = letter
  print(display)

check_letter()

for item in display:
  while item == "_":
    guess = input("Guess a letter: ").lower()
    check_letter()

print("You've Won")
  

>Solution :

item is a copy of your display element. This may be what you want

for i in range(word_length):
  while display[i] == "_":
    guess = input("Guess a letter: ").lower()
    check_letter()