def categories_to_string(categories, queryset=False):
    """
    Args:
        categories: [{"title": "Business"}, ...] OR
                    [models.Category] (if queryset=True)
    Returns:
        ['<category.title', ...]
    """
    if queryset:
        new_categories = [i.title for i in categories]
    else:
        new_categories = [i['title'] for i in categories]
    return str(sorted(new_categories))