LaravelFCM\Message\Topics::topicsForFcm PHP Method

    private function topicsForFcm($conditions)
    {
        $condition = "";
        foreach ($conditions as $partial) {
            if (array_key_exists('condition', $partial)) {
                $condition .= $partial['condition'];
            }
            if (array_key_exists('first', $partial)) {
                $topic = $partial['first'];
                $condition .= "'{$topic}' in topics";
            }
            if (array_key_exists('open_parenthesis', $partial)) {
                $condition .= $partial['open_parenthesis'];
            }
            if (array_key_exists('topic', $partial)) {
                $condition .= $this->topicsForFcm($partial['topic']);
            }
            if (array_key_exists('close_parenthesis', $partial)) {
                $condition .= $partial['close_parenthesis'];
            }
        }
        return $condition;
    }