Using LLMs to extract structured data from text

import os

import requests
from bs4 import BeautifulSoup

def extract_pdf_url(url):
    try:
        response = requests.get(url)
        response.raise_for_status()
    except Exception as e:
        raise e

    soup = BeautifulSoup(response.text, "html.parser")

    pdf_url = soup.find("a", {"class": "btn btn-primary btn-lg"})["href"]

    if pdf_url:
        return pdf_url
    else:
        raise Exception("PDF URL not found")

extract_pdf_url("https://www.csis.org/programs/strategic-technologies-program/significant-cyber-incidents")

TypeError: 'NoneType' object is not subscriptable