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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 _find_player_id(self, row):
 """ Find the player's ID. Find the player's ID as embedded in the 'data-append-csv' attribute, such as 'zettehe01' for Henrik Zetterberg. Parameters row : PyQuery object A PyQuery object representing a single row in a boxscore table for a single player. Returns ------- str Returns a ``string`` of the player's ID, such as 'zettehe01' for Henrik Zetterberg. """

        player_id = row('th').attr('data-append-csv')
        if not player_id:
            player_id = row('td').attr('data-append-csv')
        return player_id