public function validateUserData($userData)
    {
        $this->assertRequired($userData, "pwhash");
        $this->assertString($userData, "pwhash");
        
        // All remaining options are optional
        $this->assertString($userData, "email");
        $this->assertArray($userData, "attributes");
        $this->assertString($userData, "encoder");
        $this->assertBool($userData, "pwreset");
        $this->assertArrayOfStrings($userData, "groups");
        $this->assertString($userData, "displayName");
    }