Why doesn't Breakdowns region work in Facebook API?

Question

Facebook

I make such a request, and I try to split the output by region
breakdowns=region
but it doesn’t work, at the company level, if you do it instead of , then it will work. Maybe I'm not matching the request correctly?

<business-id>/owned_ad_accounts?fields=account_id,campaigns.limit(1000){insights{actions,action_values,spend,frequency,impressions,clicks,ctr,cpp,cpm,cpc,cost_per_action_type,cost_per_inline_link_click,cost_per_inline_post_engagement,cost_per_outbound_click,cost_per_unique_action_type,cost_per_unique_click}}&breakdowns=region&limit=1000

Thanks for answers!