[Exim] item list in db files ?

hi,

say i want to put an item list into a dbm file, for speed reasons.
reading spec6.2, it's clear that an item list is not to be confused
with a key-lookup db.

now, if i can put an item list into a db file (can i ? does it make
sense?), how do i do it ? if i can, i suppose the keys will be the
items, but what will be the corresponding values ? "f00bar" ? then
what ? do i get an item list from this just as say "local_domains =
dbm;/etc/exim/local_domains.db" ?

i think i'm very confused here.. could someone please sched some light
?

TIA,

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