On 2022-01-16 08:27, Steven D'Aprano wrote:
[snip]
>>>> dis.dis("frozenset({1, 2, 3})")
>    1           0 LOAD_NAME                0 (frozenset)
>                2 BUILD_SET                0
>                4 LOAD_CONST               0 (frozenset({1, 2, 3}))
>                6 SET_UPDATE               1
>                8 CALL_FUNCTION            1
>               10 RETURN_VALUE
>
> Got that? To create a frozenset of literals, first the compiler creates
> a frozenset constant containing what you wanted. Then at runtime, it:
>
> - looks up frozenset in globals and builtins;
> - loads the pre-prepared frozenset (which is exactly what we want);
> - creates a new set from that frozenset;
> - calls the frozenset() function on that set to create a new frozenset
>    that duplicates the pre-prepared one;
> - and finally garbage-collects the temporary set.
>
[snip]

Not quite as bad as that:

 >>> f = frozenset({1, 2, 3})
 >>> f is frozenset(f)
True
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