public function displayName()
    {
        if (! empty($this->first_name) && ! empty($this->last_name)) {
            return $this->first_name.' '.$this->last_name;
        }

        if (! empty($this->first_name) && ! empty($this->last_initial)) {
            return $this->first_name.' '.$this->last_initial.'.';
        }

        return $this->id;
    }