protected function loadProfile($identifier = null)
    {
        if (!$identifier) {
            $identifier = 'generic';
        }

        if (isset($this->profiles[$identifier])) {
            $this->currentProfile = $this->profiles[$identifier];
        } else {
            $this->currentProfile        = new SgProfile();
            $this->profiles[$identifier] = $this->currentProfile;
        }

        return $this->currentProfile;
    }