File upload via Pipedrive API - powershell

Question

I need to include the lead_id in the body with the file content. The file uploads well when I use
$data = Invoke-RestMethod -Uri $URL -Method 'Post' -ContentType "multipart/form-data; boundary=`"$boundary`"" -Body $BodyLines.
Naturally the file is not attached to the lead. When I use
$data = Invoke-RestMethod -Uri $URL -Method 'Post' -ContentType "multipart/form-data; boundary=`"$boundary`"" -Body $Body
I always get error 400. Specification of $Body is wrong, but how?
#URL for Deal listing with your $company_domain and $api_token variables
$URL = 'https://' + $company_domain + '.pipedrive.com/api/v1/files?api_token=' + $api_token
$URL
#
$FilePath = $LOCALpath + "\webtilaus\Tarjouspyynto_2023-02-03_09-50-44.txt"
$data =#()
$fileBytes = [System.IO.File]::ReadAllBytes($FilePath);
$fileEnc = [System.Text.Encoding]::GetEncoding('UTF-8').GetString($fileBytes);
$boundary = [System.Guid]::NewGuid().ToString();
$LF = "`r`n";
""
$BodyLines = (
"--$boundary",
"Content-Disposition: form-data; name=`"file`"; filename=`"temp.txt`"",
"Content-Type: application/octet-stream$LF",
$fileEnc,
"--$boundary--"+ $LF
) -join $LF
$Body = #{
"deal_id" = "25"
"file" = $bodyLines
}
$data = Invoke-RestMethod -Uri $URL -Method 'Post' -ContentType "multipart/form-data; boundary=`"$boundary`"" -Body $BodyLines # This uploads
$data = Invoke-RestMethod -Uri $URL -Method 'Post' -ContentType "multipart/form-data; boundary=`"$boundary`"" -Body $Body # This gives error 400`