Forum OpenACS Development: new CrClass description issue

hy there, i have new class for creating,... products, writen in xotcl
the code is bellow:

and if i want to create new item in db. i use this code.
for example:

::im::Product create product
::product set name "New product test name"
::product set title "New product test title"
::product set description "New product test description"
::product set price "11"
::product set delivery_time "10"
::product save_new

and the error that i'm getting is
how should i set description var. ?

ERROR:
can't read "description": no such variable
    while executing
"::xo::db::sql::content_item new -name $name -parent_id $parent_id -creation_user $creation_user  -creation_ip $creation_ip  -item_subtype "content_ite..."
    ("eval" body line 1)
    invoked from within
"eval ::xo::db::sql::content_item new  [[self class] set content_item__new_args]"
    invoked from within
"set item_id [eval ::xo::db::sql::content_item new  [[self class] set content_item__new_args]]"
    ("uplevel" body line 16)
    invoked from within
"uplevel 1 $transaction_code "
    (procedure "db_transaction" line 39)
    invoked from within
"db_transaction {
      $__class instvar storage_type object_type
      [self class] lock acs_objects "SHARE ROW EXCLUSIVE"
      set revision_id [db_n..."
    (procedure "save_new" line 30)
    invoked from within
"next"
    (procedure "save_new" line 3)
    ::product ::xo::db::CrCache::Item->save_new
    invoked from within
"::product save_new"
    ("uplevel" body line 7)
    invoked from within
"uplevel 1 [string map {"\\\r\n" " "} $script]"

Code:

namespace eval ::im {

	::xo::db::CrClass create ::im::Product \
		-superclass ::xo::db::CrItem \
		-id_column product_id \
		-table_name im_products \
		-pretty_namne "Im Product"

	::im::Product instproc init {} {
		my instvar product_id name title description company_id price delivery_time
		next
		my slots {
			::xo::db::CtAttribute create company_id \
				-datatype integer \
				-pretty_name "Company ID" \
				-pretty_plural "Company IDs"
			::xo::db::CrAttribute create price \
				-pretty_name "Product Price" \
				-pretty_plural "Product Prices"	
			::xo::db::CrAttribute create delivery_time \
				-datatype date \
				-pretty_name "Product Delivery Time" \
				-pretty_plural "Product Delivery Times"	
		}
	}
		
	::im::Product ad_instproc save_new {} {
		my instvar product_id name title description company_id price delivery_time
		next
	}
	
	::im::Product ad_instproc save {} {
		my instvar product_id name title description company_id price delivery_time
		next
	}
}