Rev Summary day and placement filtering

Hi there,

I'm looking for an example request for a Revenue Summary report by day and placement. I've looked at both the github and taboola.com docs and have produced the below request but I'm getting a 400 response. The error is clear that my placement filter is wrong but I can't find a resolution.

Request:
https://backstage.taboola.com/backstage/api/1.0/[account_id]/reports/revenue-summary/dimensions/day/?start_date=2020-06-01&end_date=2020-06-02&placement=[placement]

Response:
{
"http_status": 400,
"message": "Filter 'placement' has invalid value",
"offending_field": "placement"
}

Thanks!