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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 best_oob_mae_weight(trees):
 """ Returns weights so that the tree with smallest out-of-bag mean absolute error """

        best = (+1e999999, None)
        for tree in trees:
            oob_mae = tree.out_of_bag_mae
            if oob_mae is None or oob_mae.mean is None:
                continue
            best = min(best, (oob_mae.mean, tree))
        best_mae, best_tree = best
        if best_tree is None:
            return
        return [(1.0, best_tree)]