Set the channelSection country using the YouTube API - youtube-api

Question

I have a YouTube channel. Within that channel I have a channelSection called "Brazil".
I want to limit that section so that only people in Brazil can view it.
In the documentation I see how to set the country parameter for a channel, but not a channelSection.
Per documentation: https://developers.google.com/youtube/v3/docs/channelSections/update
The only items I can update are:
snippet.type
snippet.style
snippet.title
snippet.position
contentDetails.playlists[]
contentDetails.channels[]
targeting.countries[]
targeting.languages[]
targeting.regions[]
Our YouTube rep wrote to us that "To set the snippet.country property for a channel resource, you actually need to update the brandingSettings.channel.country property. This setting does not affect targeting in any way."
So I am a bit confused. Do I set the channel's brandingSettings.channel.country setting to Brazil or the channelSection, and if so, how?
Update
Following the answer below, I receive the following error:
"domain": "global", "reason": "backendError", "message": "Backend Error"

Answer 1

I think they might've been confused about what you were trying to do. Changing the brandingSettings.channel property should only set
the country with which the channel is associated. [source]
I believe the correct way to do what you're asking is by adding "Brazil" to the targeting.regions[] list.
From the documentation:
targeting.countries[]: A list of ISO 3166-1 alpha-2 country codes
where the channel section is visible. [source]
Since you've already created the channelSection, you'd just use channelSections.update() to provide a channelSection resource and specify Brazil for the targeting country. According to the ISO 3166-1 country code list, the code for Brazil is "BR". Note that if you are submitting an update request and your request does not specify a value for a property that already has a value, the property's existing value will be deleted.
Afterwards, you can use channelSections.list() to check your channelSection resource and see that it should only be visible to users in Brazil (targeting.countries[] should have "BR" as the only value). Or maybe you could use some proxy extension to view the channel section from different countries to see if it's working as expected.