Help with tic-tac-toe project

[MAZambelli4353]

Hello Ive been teaching myself python for almost a month now and Im trying to implement classes into this project which is something Im new to. Its not finished but Im getting a wrong output when I try to determine if someone won. I sometimes get a random 'You won'(sometimes 2-4 of them) even though there aren't three in a row of the same letter. I feel like I dont understand how classes work anymore.

import random
class Tic:
    board=[[' ',' ',' '],[' ',' ',' '],[' ',' ',' ']]
    placement=[[0,0],[0,1],[0,2],[1,0],[1,1],[1,2],[2,0],[2,1],[2,2]]
    def __init__(self):
        pass
    def print_board(self):
        print('{}\n{}\n{}'.format(self.board[0],self.board[1],self.board[2]))
    def change_board(self,row,column):
        if player1 is self:
            self.board[row][column]='X'
        if comp is self:
            self.board[row][column]='O'
    def did_someone_win(self,letter):
        if self.board[0][0] and self.board[1][0] and self.board[2][0] == letter:
            print('You won!')
        if self.board[0][1] and self.board[1][1] and self.board[2][1] == letter:
            print('You won!')
        if self.board[0][2] and self.board[1][2] and self.board[2][2] == letter:
            print('You won!')
        if self.board[0][0] and self.board[0][1] and self.board[0][2] == letter:
            print('You won!')
        if self.board[1][0] and self.board[1][1] and self.board[1][2] == letter:
            print('You won!')
        if self.board[2][0] and self.board[2][1] and self.board[2][2] == letter:
            print('You won!')
        if self.board[0][0] and self.board[1][1] and self.board[2][2] == letter:
            print('You won!')
        if self.board[2][0] and self.board[1][1] and self.board[0][2] == letter:
            print('You won!')
        else:
            pass
game=Tic();player1=Tic();comp=Tic()

print('First move will be randomly chosen.  Enter s to start game: ')
starting_key=input('')

if starting_key is 's':
    start_game=True
else:
    start_game=False

player1_move=False;comp_move=False

if random.randint(0, 1) == 1:
    print('Player1 goes first.')
    player1_move = True
else:
    print('Computer goes first.')
    comp_move = True

while start_game:

    while player1_move:
        print('Please enter one of the possible coordinates: ',game.placement) #shows available coordinates
        var1, var2 = input("Enter your coordinates separated by a space here: ").split()#enter coordinates
        var1=int(var1);var2=int(var2)#changes inputs into int's to avoid error
        player1.change_board(var1,var2)#using class method to change board array
        game.print_board()#using method to print the board with new inputs
        game.placement.pop(game.placement.index([var1,var2]))#removes coordinates already used.
        game.did_someone_win('X')#This is what doesnt work as I get 'You won' randomly sometimes.
        comp_move=True
        player1_move=False
    while comp_move:
        print('Computers move.')
        comp_choice = random.choice(game.placement)#randomly chooses computer's choice
        comp.change_board(comp_choice[0],comp_choice[1])#using class method to change board array
        game.placement.pop(game.placement.index([comp_choice[0], comp_choice[1]]))#remove used coordinates
        game.print_board()
        print(game.placement)
        game.did_someone_win('O')#Again doesnt work properly cant figure out why
        player1_move = True
        comp_move=False
/python]
[hr]
[python]
import random
class Tic:
    board=[[' ',' ',' '],[' ',' ',' '],[' ',' ',' ']]
    placement=[[0,0],[0,1],[0,2],[1,0],[1,1],[1,2],[2,0],[2,1],[2,2]]
    def __init__(self):
        pass
    def print_board(self):
        print('{}\n{}\n{}'.format(self.board[0],self.board[1],self.board[2]))
    def change_board(self,row,column):
        if player1 is self:
            self.board[row][column]='X'
        if comp is self:
            self.board[row][column]='O'
    def did_someone_win(self,letter):
        if self.board[0][0] and self.board[1][0] and self.board[2][0] == letter:
            print('You won!')
        if self.board[0][1] and self.board[1][1] and self.board[2][1] == letter:
            print('You won!')
        if self.board[0][2] and self.board[1][2] and self.board[2][2] == letter:
            print('You won!')
        if self.board[0][0] and self.board[0][1] and self.board[0][2] == letter:
            print('You won!')
        if self.board[1][0] and self.board[1][1] and self.board[1][2] == letter:
            print('You won!')
        if self.board[2][0] and self.board[2][1] and self.board[2][2] == letter:
            print('You won!')
        if self.board[0][0] and self.board[1][1] and self.board[2][2] == letter:
            print('You won!')
        if self.board[2][0] and self.board[1][1] and self.board[0][2] == letter:
            print('You won!')
        else:
            pass
game=Tic();player1=Tic();comp=Tic()

print('First move will be randomly chosen.  Enter s to start game: ')
starting_key=input('')

if starting_key is 's':
    start_game=True
else:
    start_game=False

player1_move=False;comp_move=False

if random.randint(0, 1) == 1:
    print('Player1 goes first.')
    player1_move = True
else:
    print('Computer goes first.')
    comp_move = True

while start_game:

    while player1_move:
        print('Please enter one of the possible coordinates: ',game.placement) #shows available coordinates
        var1, var2 = input("Enter your coordinates separated by a space here: ").split()#enter coordinates
        var1=int(var1);var2=int(var2)#changes inputs into int's to avoid error
        player1.change_board(var1,var2)#using class method to change board array
        game.print_board()#using method to print the board with new inputs
        game.placement.pop(game.placement.index([var1,var2]))#removes coordinates already used.
        game.did_someone_win('X')#This is what doesnt work as I get 'You won' randomly sometimes.
        comp_move=True
        player1_move=False
    while comp_move:
        print('Computers move.')
        comp_choice = random.choice(game.placement)#randomly chooses computer's choice
        comp.change_board(comp_choice[0],comp_choice[1])#using class method to change board array
        game.placement.pop(game.placement.index([comp_choice[0], comp_choice[1]]))#remove used coordinates
        game.print_board()
        print(game.placement)
        game.did_someone_win('O')#Again doesnt work properly cant figure out why
        player1_move = True
        comp_move=False

---

Just figured out it was the if statements and that the 'ands' didnt pool all of the other coordinates, only the last one. Anyway, any comments or advice to improve my code would be appreciated!- thanks