OSB - XQuery - line 7, col 2: {err}FORG0005: expected exactly 1 item, got 0

Question

Hi,
I am trying to execute the below sample XQuery. Eclipse designer does not show any error. However on executing the XQuery, I get the following error "+Error executing the XQuery transformation: line 7, column 2: {err}FORG0005: expected exactly one item, got 0 items+". Appreciate your help.
xquery version "1.0" encoding "UTF-8";
declare namespace xf = "http://tempuri.org/OSB%20Project%201/Ids/";
declare function xf:Ids()
as element() {*
*     let $abc := <catalog><product dept="MEN"><number>784</number><name language="en">Cotton Dress Shirt</name><colorChoices>white gray</colorChoices><desc>Our favorite shirt!</desc></product></catalog>*
*     for $product in $abc/catalog/product*
*     let $name := $product/name*
*     where $product/@dept = "ACC"*
*     order by $name*
*     return $name*
xf:Ids()

Answer 1

Thanks, for the answer.
I just tweeked my XQuery:Var = $abc a little and ended up with same issue. Request your help again.
xquery version "1.0" encoding "UTF-8";
declare namespace xf = "http://tempuri.org/OSB%20Project%201/Ids/";
declare function xf:Ids() as element(*)? {
let $abc := +<catalog><product dept="MEN" xmlns="http://datypic.com/prod"><number>784</number><name language="en">Cotton Dress Shirt</name><colorChoices>white gray</colorChoices><desc>Ou<i>favorite</i> shirt! </desc></product><product dept="ACC"><number>563</number><name language="en">Floppy Sun Hat</name></product><product dept="ACC"><number>443</number><name language="en">Deluxe Travel Bag</name></product><product dept="MEN"><number>784</number><name language="en">Cotton Dress Shirt</name><colorChoices>white gray</colorChoices><desc>Ou<i>favorite</i> shirt! </desc></product><product dept="WMN"><number>557</number><name language="en">Fleece Pullover</name><colorChoices>navy black</colorChoices></product></catalog>+
--(:<catalog><product dept="ACC"><number>784</number><name language="en">Cotton Dress Shirt</name><colorChoices>white gray</colorChoices><desc>Our favorite shirt!</desc></product></catalog>:)--
for $product in $abc/product
let $name := $product/name
where $product/@dept = "ACC"
order by $name
return $name
xf:Ids()