Importing Text File For Conways Game Of Life

Question

I am trying to import a text file to use as a board in Conway's game of life, I have 2 functions, one to read the file, the pretty print, to print the board out so it's user friendly. Can someone spot where I am going wrong? This is for python 2.7.

def read_game_board(game_file):
    board = open('grid0.txt')
    game_file = board.readlines()
    return 

def pretty_print(b):
    pretty_len = len(b)
    for x in range(0, pretty_len):
        for y in range(pretty_len):
            print [x][y]
        print '/n'

def main(name_of_file):
    b = read_game_board(board)
    run_game()

This is what the text file looks like:

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---xx-----
---xx-----
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