curl --request POST \
  --url https://api.example.com/api/albums/{album_id}/assets \
  --header 'Content-Type: application/json' \
  --data '
{
  "asset_ids": [
    "<string>"
  ]
}
'

{
  "added_assets": [
    "<string>"
  ],
  "duplicate_assets": [
    "<string>"
  ]
}