curl --request POST \
  --url https://api.interchange.io/api/v2/buyer/campaigns/{campaignId}/creative-collections/{collectionId}/members \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "members": [
    {
      "member_id": "<string>",
      "label": "<string>",
      "metadata": {}
    }
  ]
}
'

{
  "collection": {
    "collection_id": "<string>",
    "name": "<string>",
    "member_count": 4503599627370495,
    "creative_count": 4503599627370495,
    "asset_count": 4503599627370495,
    "attached_campaign_count": 4503599627370495,
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z",
    "campaign_id": "<string>",
    "brand_agent_id": "<string>",
    "description": "<string>",
    "metadata": {},
    "members": [
      {
        "member_id": "<string>",
        "created_at": "2023-11-07T05:31:56Z",
        "updated_at": "2023-11-07T05:31:56Z",
        "label": "<string>",
        "metadata": {},
        "creative": {
          "creative_id": "<string>",
          "name": "<string>",
          "created_at": "2023-11-07T05:31:56Z",
          "updated_at": "2023-11-07T05:31:56Z",
          "asset_count": 3,
          "campaign_id": "<string>",
          "format_id": {
            "id": "<string>",
            "agent_url": "<string>",
            "width": 123,
            "height": 123,
            "duration_ms": 123
          },
          "template_id": "<string>",
          "brand_domain": "<string>",
          "preview_url": "<string>",
          "requires_upgrade": true,
          "sync_status": {
            "synced": true,
            "agent_count": 0
          },
          "target_format_ids": [
            {
              "id": "<string>",
              "agent_url": "<string>",
              "width": 123,
              "height": 123,
              "duration_ms": 123
            }
          ]
        }
      }
    ],
    "attachments": [
      {
        "campaign_id": "<string>",
        "collection_id": "<string>",
        "created_at": "2023-11-07T05:31:56Z",
        "updated_at": "2023-11-07T05:31:56Z",
        "metadata": {}
      }
    ]
  },
  "added_count": 4503599627370495,
  "removed_count": 4503599627370495,
  "attached": {
    "campaign_id": "<string>",
    "collection_id": "<string>",
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z",
    "metadata": {}
  },
  "assigned_count": 4503599627370495,
  "legacy_members_excluded": 4503599627370495
}