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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 open_session(self):
 """ Opens a db session and returns it """

        from .dal import get_session

        cfg = Config()
        cfg.logger = self.logger
        db_path = cfg.get(ConfigKeys.asset_allocation_database_path)

        self.session = get_session(db_path)
        return self.session