Tictactoe game written in Python

tictactoe.py

import random
import time

win_combos = [[1,2,3],
              [4,5,6],
              [7,8,9],
              [1,5,9],
              [3,5,7],
              [1,4,7],
              [2,5,8],
              [3,6,9]]
##
##
## ao passar para classe variaveis ficam no __init__
##
def initBoard():
    clearWindow()
    global new_a_board, new_a_unused, \
           new_array_X, new_array_O
    new_a_board = [' '] * 10
    new_a_unused = [1,2,3,4,5,6,7,8,9]
    new_array_X = [] 
    new_array_O = []
    #print '_|_|_\n_|_|_\n | |'

def humanPlay(a):
    print 'Human\'s time to play'
    while True:
        print 'Select from available positions\n', \
              a
        position = int(raw_input('> '))
        if position in a:
            return position
        else:
            print "Wrong move!"

def printBoard(a):
    clearWindow()
    print ' ',a[1],a[2],a[3]
    print ' ',a[4],a[5],a[6]
    print ' ',a[7],a[8],a[9]

def randomPlay(a):
    pos = random.choice(a)
    return pos

def checkMove(pos):
    if new_a_board[pos] in new_a_unused:
        return True
    else:
        False

def checkWin(player):
    if player == 'X':
        for i in win_combos:
            if i[0] in new_array_X and \
               i[1] in new_array_X and \
               i[2] in new_array_X:
                print "Player1 wins!"
                time.sleep(2)
                return True
    else:
        for i in win_combos:
            if i[0] in new_array_O and \
               i[1] in new_array_O and \
               i[2] in new_array_O:
                print "Player2 wins!"
                time.sleep(2)
                return True
    return False

def logMove(pos, player):
    print player, 'in position', pos

def move(pos, player):
    new_a_board[pos] = player
    if player == 'X':
        new_array_X.append(pos)
    else:
        new_array_O.append(pos)
    new_a_unused.remove(pos)

def gameType():
    print "Human vs Human"
    print "Human vs Robot"
    print "Robot vs Robot"


def firstToPlay():
    print "First to Play:\n", \
          "1 - Human\n", \
          "2 - Robot"
    n = int(raw_input('> '))
    if n is 1:
        return 1
    elif n is 2:
        return 0

def clearWindow():
    print "\033c"

def main():
    var = firstToPlay()
    initBoard()
    finished = False
    while not finished:
        time.sleep(1)
        var += 1
        if var%2:
            pl='X'
            ps = randomPlay(new_a_unused)
        else:
            pl='O'
            ps = humanPlay(new_a_unused)
        #ps = randomPlay(new_a_unused, pl)
        move(ps,pl)
        printBoard(new_a_board)
        logMove(ps, pl)
        if len(new_a_unused) <=4 :
            finished = checkWin(pl)
            if len(new_a_unused) is 0 and not finished:
                print "Nobody wins!"
                time.sleep(1)
                var = 0
                initBoard()

if __name__ == "__main__":
    while True:
        main()