Add missing ocr model

app.py

@@ -32,6 +32,7 @@ def ocr_pdf_img_document(pdf_or_img_url:str)-> str:
         pdf_or_img_url: the url address of the pdf to ocr
     """
     client = Mistral(api_key=api_key)
+    ocr_model ="mistral-ocr-latest"
 
     try:   # Apply OCR to the PDF URL
         ocr_response = client.ocr.process(