Thanks for this great work.

In chapter 8.2.2 (Substitutability), you gave the following example,

and further noted the following words:

You could pull more tricks out of your sleeve to make this work,
but consider that this might be a better case for composition.
A snail *has-a* shell, after all. 

Is this code below along the lines of what you were thinking?
Instead of making Snail inherit from Slug, the shell
behavior should be composed into the snail class, and there
shouldn't be any need for inheritance.

class Shell:
    size = None

class Snail:
    def __init__(self, name, shell):
        self.name = name
        self.shell_size = shell.size

Snail("Hafsoh", Shell())

Issue

Function only works if you have at least 3 names. otherwise (e.g. if have only 2):
'person1, and person2'

In method select the query never gets a closing ;
The query works but you should always add the semicolon.
To fix it, add this right before the return statement:
query += ';'

The function print_options() should start the enumeration with 1 to match the choices (fixed code shown below), otherwise it's a bug.

def print_options():
    print('\n'.join(f'({i}) {option.title()}' for i, option in enumerate(OPTIONS, 1)))

The timing module by default executes the statement for 1 million times (link): timeit.timeit(stmt='pass', setup='pass', timer=<default timer>, number=1000000)

So the output of this line in the timing.py module should be in us not ms:

result = timeit(setup=setup, stmt=statement)
print(f'Took an average of {result}ms')

Why is the Greeter class including an init with name? The specification of the Greeter class in the text above does not say to include Hi, my name is <name>... but it says Hi, welcome to <store>...

In chapter 8 we introduce the Command abstract base class and add data=None args to some of the execute methods (e.g. CreateBookmarksTableCommand.execute) to satisfy LSP.

However, AddBookmarkCommand.execute still has an additional timestamp arg.

Should timestamp also be passed in as part of the data dict to keep the method signature consistent with the base?

class AddBookmarkCommand(Command):
    def execute(self, data):
        data["date_added"] = data.get("date_added") or datetime.utcnow().isoformat()
        db.add("bookmarks", data)
        return "Bookmark added!"

Thanks!