Answered Query: xPDO error - A is not subclass of B

<?xml version="1.0" encoding="UTF-8"?>
<model package="pms" baseClass="xPDOObject" platform="mysql" tablePrefix="pms_" defaultEngine="MyISAM" version="1.1">
    <object class="pmsMapRecord" table="records" extends="xPDOSimpleObject">
        <field key="package" dbtype="varchar" precision="100" phptype="string" null="false" default="" />
        <field key="class_key" dbtype="varchar" precision="100" phptype="string" null="false" default="" />
        <field key="migrate_id" dbtype="varchar" precision="100" phptype="string" null="false" default="" />
        <field key="local_pk" dbtype="int" precision="11" phptype="string" null="false" default="" />
        <field key="updated" dbtype="int" precision="16" phptype="string" null="false" default="0" />
        
        <alias key="local_id" field="local_pk" />
        
    </object>
</model>

// Check for an existing record
       $record = self::$modx->getObject('pmsMapRecord',array(
                'package' => $pkgName,
                'class_key' => $classKey,
                'local_pk' => $localId
            ));
       if($record !== false){
           // Return the existing id
           return $record->get('migrate_id'); 
       };
       // Generate a new id
       $all = self::$modx->getCollection('pmsMapRecord',array(
                'package' => $pkgName,
                'class_key' => $classKey
            ));
       $newId = "$classKey-".count($all);
       // Save new record
       $new = self::$modx->newObject('pmsMapRecord',array(
                'package' => $pkgName,
                'class_key' => $classKey,
                'local_id' => $localId,
                'migrate_id' => $newId,
                'updated' => time()
            ));
       $new->save();