def METHOD_NAME(pgn_file="chess_masters_WCC.pgn.bz2"):
    """Read chess games in pgn format in pgn_file.
    Filenames ending in .bz2 will be uncompressed.
    Return the MultiDiGraph of players connected by a chess game.
    Edges contain game data in a dict.
    """
    import bz2
    G = nx.MultiDiGraph()
    game = {}
    with bz2.BZ2File(pgn_file) as datafile:
        lines = [line.decode().rstrip("\r\n") for line in datafile]
    for line in lines:
        if line.startswith("["):
            tag, value = line[1:-1].split(" ", 1)
            game[str(tag)] = value.strip('"')
        else:
            # empty line after tag set indicates
            # we finished reading game info
            if game:
                white = game.pop("White")
                black = game.pop("Black")
                G.add_edge(white, black, **game)
                game = {}
    return G