SPARQL VALUES BLOCK AND GRAPH - sparql

Question

I am trying to replace the value of code_type when it is empty and belongs to ifcowl:IfcSite with "INF" via this attempt. I don't know if this is possible.
First, I get the code_type values I need and I use the "values" block to replace the values
However, some values are empty and among these empty values, I have to replace the empty value by "INF" but only for ifcowl = IfcSite
Here is my attempt and thank you in advance for your help :
select ?code_type ?gid ?VALUE1 ?TEST
PREFIX ifcowl: <http://www.buildingsmart-tech.org/ifcOWL/IFC2X3_TC1#>
PREFIX express: <https://w3id.org/express#>
PREFIX blabla: <https://www.blabla.fr/>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX iso23386: <https://www.iso.org/standard/iso23386#>
{
?o a ?class .
GRAPH blabla:optimized {
OPTIONAL {?o blabla:SEQ_GUID ?gid}
OPTIONAL {?o blabla:code_type ?code_type}
OPTIONAL {?o blabla:VALUE1 ?VALUE1}
FILTER (?code_type IN
(""^^xsd:string, "ATE_PCO"^^xsd:string, "ATE_SCA"^^xsd:string, "ATE_TNT"^^xsd:string))
}
optional {
values (?code_type ?TEST) {
("" "ZONE" && ?class = ifcowl:IfcSite)
}
}
optional {
values (?code_type ?TYPE) {
("ATE_PCO" "PCO")
("ATE_SCA" "CABLE")
("ATE_TNT" "TNT")
}
values (?code_type ?NOMOS) {
("ATE_PCO" "ABC")
("ATE_SCA" "BDC")
("ATE_TNT" "EDG")
}
}
}