While Converting Tiff to pdf in python the pdf gets blacked

Question

enter image description hereThats the code, the problem is after saving the pdf it appears black. But some tiffs while conversion are saved and converted properly, But some go black.

 import json
 import urllib.parse
import boto3
 import os
 import img2pdf
from PIL import Image 

path = r"SI-1.tif"

im = Image.open(path)

(file1, ext) = os.path.splitext(path)
print(file1)
print(ext)
pdf_Path = "static\A.pdf"
if ext.lower() == '.tif' or ext.lower() == '.jpg':

    pdf_bytes = img2pdf.convert(im.filename)

    # opening or creating pdf file 
    file = open(pdf_Path, "wb") 
        
    # writing pdf files with chunks 
    file.write(pdf_bytes)