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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def handle_node(pos, node):
    'A node can either add B+W stones, play as B, or play as W.'
    props = node.properties
    black_stones_added = [coords.from_sgf(
        c) for c in props.get('AB', [])]
    white_stones_added = [coords.from_sgf(
        c) for c in props.get('AW', [])]
    if black_stones_added or white_stones_added:
        return add_stones(pos, black_stones_added, white_stones_added)
    # If B/W props are not present, then there is no move. But if it is present and equal to the empty string, then the move was a pass.
    elif 'B' in props:
        black_move = coords.from_sgf(props.get('B', [''])[0])
        return pos.play_move(black_move, color=go.BLACK)
    elif 'W' in props:
        white_move = coords.from_sgf(props.get('W', [''])[0])
        return pos.play_move(white_move, color=go.WHITE)
    else:
        return pos