How to use Collection::ofType

Hi,
I can't make ofType or ofOneOfTheseTypes work.
Let say I have the following code:

content:
    items: '@self.modular'

{% for tile in page.collection().ofType('home_introduction') %}
    {{ tile.content }}
{% endfor %}

The result is empty.
Why doesn't it work? When I take out ofType(), everything is fine.
But I need to filter the collection to add a new modular content into the page.

Also what I ultimately want to achieve is something like this, with ofOneOfTheseTypes, but my syntax seems wrong:

{% for tile in page.collection().ofOneOfTheseTypes({'home_introduction', 'home_item'}) %}
    {{ tile.content }}
{% endfor %}

@ontime:
{% for tile in page.collection().ofOneOfTheseTypes({'home_introduction', 'home_item'}) %}
{{ tile.content }}
{% endfor %}

Collection::ofOneOfTheseTypes() accepts an Array. You're passing a (malformed) object. Try

{% for tile in page.collection().ofOneOfTheseTypes(['home_introduction', 'home_item']) %}

The first example seems fine. What's your page structure? (a screenshot is fine)

Thanks for the array syntax tip, I am new to twig.
With the right syntax, now both methods give me an empty result.

Here is my templates structure. Is this what you meant ?

<img src="//cdck-file-uploads-canada1.s3.dualstack.ca-central-1.amazonaws.com/flex036/uploads/getgrav/original/1X/40c20d85bd807f12bdc113031fe6a689936789b9.png" width="303" height="396">

Looks right. If your page has a home_introduction.md modular child page, it should show up.

Is it in a folder starting with an _ (underscore)? Can you paste the page structure as well?

Yes, the folders of the modular pages are all prefixed with an _.

Here is the structure of the page:

<img src="//cdck-file-uploads-canada1.s3.dualstack.ca-central-1.amazonaws.com/flex036/uploads/getgrav/original/1X/6b61ae9fe6abb27647f3ae41004c3318680eed5f.png" width="431" height="203">

PM me your user/pages folder, I'll check directly