(maps/select-keys {a 1 b 2 c 3} [a c])
(maps/select-keys {/a 1 b 2} ["/a"])
(maps/select-keys {a 1} [missing a])
(maps/select-keys {/a/b 2 a {b 1}} ["/a/b"])
(maps/select-keys
  {<!b>
   a null
   c 3}
  [b a a])
(maps/select-keys null [a])
(maps/select-keys {a 1} [])
(maps/select-keys {a 1} null)