Update app.py

app.py

@@ -43,7 +43,7 @@ def get_content_type(url):
 
 def perform_ocr_file(file, ocr_method="Mistral OCR"):
     if ocr_method == "Mistral OCR":
-        if lower(file.name).endswith('.pdf'):
+        if file.name.lower().endswith('.pdf'):
             uploaded_pdf = client.files.upload(
                 file={
                     "file_name": file.name,
@@ -62,7 +62,7 @@ def perform_ocr_file(file, ocr_method="Mistral OCR"):
             )
             client.files.delete(file_id=uploaded_pdf.id)
 
-        elif lower(file.name).endswith(('.png', '.jpg', '.jpeg')):
+        elif file.name.lower().endswith(('.png', '.jpg', '.jpeg')):
             base64_image = encode_image(file.name)
             ocr_response = client.ocr.process(
                 model="mistral-ocr-latest",