public function output()
    {
        // By default, the shortcode takes the current lead as the input
        $lead = Conversation::get('lead');

        // If id provided, the shortcode will find the lead with the id.
        if (isset($this->attributes['id'])) {
            $id   = $this->attributes['id'];
            $lead = LeadModel::whereUserId($id)->first();
        }

        // Loop through attributes and get or set data
        foreach ($this->attributes as $key => $value) {
            if ($key === 'id') {
                continue;
            }

            // Note that if $value isn't provided, it will get data.
            return $lead->data($key, $value);
        }
    }