Can't break the while loop in python - python-3.x

Question

I am building a tic-tac-toe. I have almost finished it but I cannot break the while loop in the end. I have turned win into True. But the if statement in the while loop is not working.
board = [[1,2,3],[4,"X",6],[7,8,9]]
win = False
def DisplayBoard(board):
def printborder():
print("+-------+-------+-------+")
def printline():
print("| | | |")
def printitem(board,row):
print("| ",board[row][0]," | ",board[row][1]," | ",board[row][2]," |", sep="")
printborder()
printline()
printitem(board,0)
printline()
printborder()
printline()
printitem(board,1)
printline()
printborder()
printline()
printitem(board,2)
printline()
printborder()
def EnterMove(board):
while True:
move = int(input("Enter your move: "))
for i in range(len(board)):
for j in range(len(board[i])):
if board[i][j]==move:
board[i][j]="O"
return None
def MakeListOfFreeFields(board):
freefield = []
for i in range(len(board)):
for j in range(len(board[i])):
for k in range(1,10):
if board[i][j] == k:
freefield.insert(0,k)
return freefield
def VictoryFor(board, sign):
def whowin(sign):
if sign == "O":
print("Player wins.")
win = True
elif sign == "X":
print("Computer wins.")
win = True
def checkvertical(board):
for i in range(3):
if board[0][i]==board[1][i]==board[2][i]:
whowin(sign)
def checkhorizontal(board):
for i in range(3):
if board[i][0]==board[i][1]==board[i][2]:
whowin(sign)
def checkdiagonal(board):
if board[0][0]==board[1][1]==board[2][2] or board[0][2]==board[1][1]==board[2][0]:
whowin(sign)
checkvertical(board)
checkhorizontal(board)
checkdiagonal(board)
def DrawMove(board):
from random import randrange
while True:
ran = randrange(1,10)
if ran in MakeListOfFreeFields(board):
for i in range(len(board)):
for j in range(len(board[i])):
if board[i][j]==ran:
board[i][j]="X"
return None
DisplayBoard(board)
while True:
EnterMove(board)
DisplayBoard(board)
VictoryFor(board, "O")
if win==True:
break
DrawMove(board)
DisplayBoard(board)
VictoryFor(board, "X")
if win==True:
break
print("ended")
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Answer 1

In your whowin function (inside of VictoryFor) you simply create a local win variable. If you want to refer to the global one, you need to tell Python to do so:
def whowin(sign):
global win # <---- add this
if sign == "O":
print("Player wins.")
win = True
elif sign == "X":
print("Computer wins.")
win = True