add code to install natsort

app.py

@@ -1,11 +1,14 @@
 import time
 import streamlit as st
+import subprocess
 import numpy as np
 from PIL import Image
 from io import BytesIO
 from models.HAT.hat import *
 from models.RCAN.rcan import *
 from models.SRGAN.srgan import *
+
+subprocess.call('pip install natsort', shell=True)
 from models.SRFlow.srflow import * 
 
 # Initialize session state for enhanced images