Forum OpenACS Q&A: setting default values in ad_page_contract

on the second example, using bind variables in your query, I am trying to specify a default value of "1" for user_id.

The documentation at:
https://openacs.org/api-doc/proc-view?proc=ad_page_contract&source_p=1&version_id=

shows that the way to specify default values is this format:
{name[:flag,flag,flag] default}

I have tried like so:
user_id:integer "1"
and also like so:
user_id:integer 1

But the page outputs:
We had some problems with your input:

* You must supply a value for user_id
* You must supply a value for 1
Instead of using the default value.

What am I doing wrong?

Thank you.

ad_page_contract {
uses bind variables in a query
@author Matthew Smith
} {
user_id:integer "1"
} -properties {
users:onerow
}

set query " select
first_name, last_name
from
ad_template_sample_users
where user_id = :user_id"

db_1row users_query $query -column_array users