How to use the d20.utils.tree_map function in d20

dice_ast = _upcast_scaled_dice(self, autoctx, dice_ast)

        # -mi # (#527)
        if mi_arg:
            dice_ast = d20.utils.tree_map(_mi_mapper(mi_arg), dice_ast)

        # -d #
        if d_arg:
            d_ast = d20.parse(d_arg)
            dice_ast.roll = d20.ast.BinOp(dice_ast.roll, '+', d_ast.roll)

        # crit
        in_crit = autoctx.in_crit or crit_arg
        roll_for = "Damage" if not in_crit else "Damage (CRIT!)"
        if in_crit:
            dice_ast = d20.utils.tree_map(_crit_mapper, dice_ast)
            if critdice and not autoctx.is_spell:
                # add X critdice to the leftmost node if it's dice
                left = d20.utils.leftmost(dice_ast)
                if isinstance(left, d20.ast.Dice):
                    left.num += int(critdice)

        # -c #
        if c_arg and in_crit:
            c_ast = d20.parse(c_arg)
            dice_ast.roll = d20.ast.BinOp(dice_ast.roll, '+', c_ast.roll)

        # max
        if max_arg:
            dice_ast = d20.utils.tree_map(_max_mapper, dice_ast)

        # evaluate damage

# add on combatant damage effects (#224)
        if autoctx.combatant:
            effect_d = '+'.join(autoctx.combatant.active_effects('d'))
            if effect_d:
                if d:
                    d = f"{d}+{effect_d}"
                else:
                    d = effect_d

        dice_ast = copy.copy(d20.parse(self.dice))
        dice_ast = _upcast_scaled_dice(self, autoctx, dice_ast)

        if not self.hidden:
            # -mi # (#527)
            if mi:
                dice_ast = d20.utils.tree_map(_mi_mapper(mi), dice_ast)

            if d:
                d_ast = d20.parse(d)
                dice_ast.roll = d20.ast.BinOp(dice_ast.roll, '+', d_ast.roll)

            if maxdmg:
                dice_ast = d20.utils.tree_map(_max_mapper, dice_ast)

        rolled = roll(dice_ast)
        if not self.hidden:
            autoctx.meta_queue(f"**{self.name.title()}**: {rolled.result}")

        d20.utils.simplify_expr(rolled.expr)
        autoctx.metavars[self.name] = RerollableStringifier().stringify(rolled.expr.roll)

d = effect_d

        dice_ast = copy.copy(d20.parse(self.dice))
        dice_ast = _upcast_scaled_dice(self, autoctx, dice_ast)

        if not self.hidden:
            # -mi # (#527)
            if mi:
                dice_ast = d20.utils.tree_map(_mi_mapper(mi), dice_ast)

            if d:
                d_ast = d20.parse(d)
                dice_ast.roll = d20.ast.BinOp(dice_ast.roll, '+', d_ast.roll)

            if maxdmg:
                dice_ast = d20.utils.tree_map(_max_mapper, dice_ast)

        rolled = roll(dice_ast)
        if not self.hidden:
            autoctx.meta_queue(f"**{self.name.title()}**: {rolled.result}")

        d20.utils.simplify_expr(rolled.expr)
        autoctx.metavars[self.name] = RerollableStringifier().stringify(rolled.expr.roll)