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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 _prepare_first_step(self):
 """First step extra preparations. Must not be called before _prepare_step."""

        if self.townhalls:
            self._game_info.player_start_location = self.townhalls.first.position
        self._game_info.map_ramps = self._game_info._find_ramps()