Exercise 1: A macro_off MacroCommand — Possible Solution
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THE NEW COMMANDS, FOLLOWING THIS CHAPTER'S OWN SHAPE
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    class LightOffCommand:
        def __init__(self, light): self.light = light
        def execute(self): self.light.turn_off()
        def undo(self): self.light.turn_on()

    class FanOffCommand:
        def __init__(self, fan): self.fan = fan
        def execute(self): self.fan.turn_off()
        def undo(self): self.fan.turn_on()

Both mirror this chapter's own LightOnCommand/FanOnCommand exactly,
just with execute() and undo() swapped - turning something off is
undone by turning it back on, the reverse of the "on" commands this
chapter already built.

STARTING STATE AND THE NEW MACRO
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    macro_off = MacroCommand([LightOffCommand(light), FanOffCommand(fan)])

Starting with both light and fan already ON (as they were at the end
of this chapter's own macro-on example):

    after macro_off execute: light.is_on = False , fan.is_on = False
    call log after execute: ['Living Room Light OFF', 'Ceiling Fan OFF']

Both devices correctly turn off, in the order they were listed in the
macro's own command list (light, then fan) - matching this chapter's
own macro-on execute() order exactly.

VERIFYING THE UNDO, IN REVERSED ORDER
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    after macro_off undo: light.is_on = True , fan.is_on = True
    call log after undo: ['Living Room Light OFF', 'Ceiling Fan OFF',
                           'Ceiling Fan ON (undo)', 'Living Room Light ON (undo)']

Both devices correctly turn back on - and the undo log confirms the
fan (turned off second) is undone first, and the light (turned off
first) is undone last, exactly the same reversed-order pattern this
chapter's own macro-on example demonstrated, now confirmed for a
macro built from the opposite pair of commands.

WHY THIS WORKS AS AN ANSWER
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The new commands are built by mirroring this chapter's own existing
on-command classes with execute()/undo() reversed, the macro is
verified turning both devices off in the listed order, and its undo
is verified reversing them in the opposite order - directly confirming
MacroCommand's own reversed-undo behavior isn't specific to the
particular on-commands this chapter originally demonstrated it with.