Can't setval() a sequence to return the first value

Hi hackers.

Is it by design that you can't setval(seq, value) a sequence to a value 
which returns the first value:

See the sample below for better explanation:

hannu=# create sequence s;
CREATE SEQUENCE
hannu=# select nextval('s'); nextval
---------       1
(1 row)
hannu=# select setval('s',1); setval
--------      1
(1 row)
hannu=# select nextval('s'); nextval
---------       2
(1 row)
hannu=# select setval('s',0);
ERROR:  setval: value 0 is out of bounds for sequence "s" 
(1..9223372036854775807)

Should it not be possible to set sequence to one below the start value 
so that you can completely reset it ?

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Hannu