Hello there, i want to display categories menu inside my products, so i'm using this code in the product view

<div class="col-md-2 bg-700">
<ul class="nav nav-pills flex-column mt16">
<li class="nav-item">
<a t-att-href="keep('/shop/',category=0)" >All Products</a>
</li>
<t t-foreach="categories" t-as="c" >
<t t-call="website_sale.categories_recursive"/>
</t>
</ul>
</div>

That works but THERE IS A PROBLEM, when i search a product using the search button and open the product i get an Error

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argument of type 'NoneType' is not iterable
Traceback (most recent call last):
  File "/home/odoo/src/odoo/odoo/addons/base/models/qweb.py", line 347, in _compiled_fn
    return compiled(self, append, new, options, log)
  File "<template>", line 1, in template_website_sale_categories_recursive_104
  File "<template>", line 7, in foreach_103
TypeError: argument of type 'NoneType' is not iterable

Error to render compiling AST
TypeError: argument of type 'NoneType' is not iterable
Template: website_sale.categories_recursive
Path: /templates/t/li/ul/t/t
Node: <t t-if="not search or c.id in search_categories_ids">
                        <t t-call="website_sale.categories_recursive"/>
                    </t>

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