curl --request POST \
  --url https://extraction-api.nanonets.com/api/v1/classify/batch \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'files=<string>' \
  --form 'categories=[{"name": "Invoice"}, {"name": "Contract"}, {"name": "Receipt"}]' \
  --form files.items='@example-file'

{
  "success": true,
  "message": "<string>",
  "batch_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "total_files": 123,
  "successful_files": 123,
  "failed_files": 123,
  "results": [
    {
      "filename": "<string>",
      "total_pages": 123,
      "pages": [
        {
          "page_number": 2,
          "category": "<string>",
          "confidence": 50,
          "reasoning": "<string>",
          "identified_category": "<string>"
        }
      ],
      "file_id": "<string>",
      "processing_time": 123,
      "error": "<string>"
    }
  ]
}