How to pass table column values to function

Hi!

Table source contains integer column. Its values should be passed to 
function for selecting data from other table.

I tried

         CREATE OR REPLACE FUNCTION 
public.TestAddAssetTransactions(dokumnrs int[])
          RETURNS int AS
         $BODY$

         with i1 as (
         INSERT INTO bilkaib (dokumnr)
         select dokumnr  from dok where dokumnr in (select * from 
unnest(dokumnrs))
         returning *
         )

         select count(*) from i1;
         $BODY$ language sql;

         create temp table bilkaib (dokumnr int ) on commit drop;
         create temp table dok (dokumnr serial primary key ) on commit drop;
         create temp table source (dokumnr int ) on commit drop;
         insert into source values (1),(2);

     select TestAddAssetTransactions( (select ARRAY[dokumnr] from 
source)::int[] )


but got error

 > ERROR: more than one row returned by a subquery used as an expression

How to pass set of integers to function? Should temp table with fixed 
name used or is there better solution?

Using Postgresql 12+

Andrus.