def get_all_categories(product_list):
    """
    Function to get a unique list of categories out of the list of products.

    :param product_list: List of products
    :return: dict with category names as keys
    """
    categories_dict = dict()
    for product in product_list:
        if product['category_name'] not in categories_dict and product['category_name']:
            categories_dict[product['category_name']] = None

    return categories_dict