Get customschema data - google-apps-script

Question

I am new to this new world of programming with GAS, I have not programmed anything for a long time and the change of structure is a bit complicated to understand. I have an app-script that reads the data of the domain users and it works very well, but it doesn't bring me the customschema fields. I've searched quite a bit in the documentation, until I found something that seemed to work.
I created a function and tried to retrieve the fields I need and it works. What it does is look up a user and fetch the data.
Then I wanted to use that function but passing it the userkey of the user in question and then return one of the fields. But it stopped working, it only brought the normal data, but from the customschema, nothing.
My function is:
function LeeUser() {
var iuserEmail = "user#midominio.com";
var test = {
"name": {
"familyName": "",
"givenName": ""
},
"password": "",
"primaryEmail": "",
"orgUnitPath": "",
"emails":[{
"type": "work",
"address": "",
}],
"customSchemas": {
"Organizacion_Interna": {
"NombreFuncionario": "",
"FechaCaducidad": ""
}
},
};
try {
test = AdminDirectory.Users.get(iuserEmail,{"projection": "full"});
console.log(test.customSchemas.Organizacion_Interna.FechaCaducidad);
} catch (err) {
Logger.log('Failed with error %s', err.message);
}
}
But when I change
function LeeUser(userEmail) {
var iuserEmail = userEmail;
var test = {
"name": {
"familyName": "",
"givenName": ""
},
"password": "",
"primaryEmail": "",
"orgUnitPath": "",
"emails":[{
"type": "work",
"address": "",
}],
"customSchemas": {
"Organizacion_Interna": {
"NombreFuncionario": "",
"FechaCaducidad": ""
}
},
};
try {
test = AdminDirectory.Users.get(iuserEmail,{"projection": "full"});
return test.customSchemas.Organizacion_Interna.FechaCaducidad;
} catch (err) {
Logger.log('Failed with error %s', err.message);
}
}
It tells me that the field is not defined.
what's the problem?
Any suggestion
Thanks in advance.