[Python] Tic-Tac-Toe

cells = [" ",
    " ",
    " ",
    " ",
    " ",
    " ",
    " ",
    " ",
    " "]
    
turn = "X"
    
def set_cell(x, y):
    cell = None
    if x == 0:
        if y == 0:
            cell = 0
        elif y == 1:
            cell = 3
        elif y == 2:
            cell = 6
    elif x == 1:
        if y == 0:
            cell = 1
        elif y == 1:
            cell = 4
        elif y == 2:
            cell = 7
    elif x == 2:
        if y == 0:
            cell = 2
        elif y == 1:
            cell = 5
        elif y == 2:
            cell = 8
        
    return int(cell)
            
def set_turn(change):
    if change == "X":
        change = "O"
    else:
        change = "X"
        
    return change
    
def get_turn(turn):
    if turn == "X":
        print ("It is player1's turn.")
    else:
        print ("It is player2's turn.")
        
def draw_grid(cell1, cell2, cell3, cell4, cell5, cell6, cell7, cell8, cell9):
    print (" " + cell1 + " | " + cell2 + " | " + cell3 + " ")
    print ("---|---|---")
    print (" " + cell4 + " | " + cell5 + " | " + cell6 + " ")
    print ("---|---|---")
    print (" " + cell7 + " | " + cell8 + " | " + cell9 + " ")
    
def instructions():
    print ("To play, simply type the column followed by the row.")
    print ("For example, if I wanted to play the top-middle piece, I would enter: 10")
    print ("To find out who's turn it is, simply type: t")
    
def check_win():
 
    #Player1 - Horizontal
    if cells[0] == "X" and cells[1] == "X" and cells[2] == "X":
        print ("Player1 wins")
        return True
    elif cells[3] == "X" and cells[4] == "X" and cells[5] == "X":
        print ("Player1 wins")
        return True
    elif cells[6] == "X" and cells[7] == "X" and cells[8] == "X":
        print ("Player1 wins")
        return True
    #Player1 - Vertical
    elif cells[0] == "X" and cells[3] == "X" and cells[6] == "X":
        print ("Player1 wins")
        return True
    elif cells[1] == "X" and cells[4] == "X" and cells[7] == "X":
        print ("Player1 wins")
        return True
    elif cells[2] == "X" and cells[5] == "X" and cells[8] == "X":
        print ("Player1 wins")
        return True
        
    #Player1 - Diagonal
    elif cells[0] == "X" and cells[4] == "X" and cells[8] == "X":
        print ("Player1 wins")
        return True
    elif cells[2] == "X" and cells[4] == "X" and cells[6] == "X":
        print ("Player1 wins")
        return True
        
    #Player2 - Horizontal
    elif cells[0] == "O" and cells[1] == "O" and cells[2] == "O":
        print ("Player1 wins")
        return True
    elif cells[3] == "O" and cells[4] == "O" and cells[5] == "O":
        print ("Player1 wins")
        return True
    elif cells[6] == "O" and cells[7] == "O" and cells[8] == "O":
        print ("Player1 wins")
        return True
    #Player2 - Vertical
    elif cells[0] == "O" and cells[3] == "O" and cells[6] == "O":
        print ("Player1 wins")
        return True
    elif cells[1] == "O" and cells[4] == "O" and cells[7] == "O":
        print ("Player1 wins")
        return True
    elif cells[2] == "O" and cells[5] == "O" and cells[8] == "O":
        print ("Player1 wins")
        return True
        
    #Player2 - Diagonal
    elif cells[0] == "O" and cells[4] == "O" and cells[8] == "O":
        print ("Player1 wins")
        return True
    elif cells[2] == "O" and cells[4] == "O" and cells[6] == "O":
        print ("Player1 wins")
        return True
    
    #No winners...
    else:
        
        blank = False
        for itms in cells:
            if itms == " ":
                blank = True
    
        if blank == False:
            return True
        else:
            return False
    
 
def set_cells():
    return [" ", " ", " ", " ", " ", " ", " ", " ", " "]
    
def reset_turn():
    return "X"
    
def new_game():
    turn = reset_turn()
    cells = set_cells()
    instructions()
    
    return [turn, cells]
    
new_game()
while True:
    response = input()
    if response == "t":
        get_turn(turn)
    else:
        cell = set_cell(int(response[0]), int(response[1]))
        
        cells[cell] = turn
        
        draw_grid(cells[0], cells[1], cells[2], cells[3], cells[4], cells[5], cells[6], cells[7], cells[8])
        
        win = check_win()
        if win == True:
            end = new_game()
            turn = end[0]
            cells = end[1]
        else:
            turn = set_turn(turn)