title: AttributeError: 'NoneType' object has no attribute 'find_all' Beautifulsoup
body: <p>I'm trying to scrape a house's price of this link : <a href="https://www.leboncoin.fr/ventes_immobilieres/offres/ile_de_france/p-2/" rel="nofollow noreferrer">https://www.leboncoin.fr/ventes_immobilieres/offres/ile_de_france/p-2/</a></p>
  
  <p>And I need to know what wrong with my program ?</p>
  
  <p>My program :</p>
  
  <pre><code>import csv
  import requests
  from bs4 import BeautifulSoup
  
  with open("bc.csv", "w", newline="") as f:
      writer = csv.writer(f)
      writer.writerow(["prix", "code_postal", "description", "nombre_pieces", "surface"]) 
      for i in range(1, 20):
          url = "https://www.leboncoin.fr/ventes_immobilieres/offres/ile_de_france/p-%s/" % i
          soup = BeautifulSoup(requests.get(url).text, "html.parser")
          repo = soup.find(class_="undefined")
          for repo in repo.find_all("li", attrs={"itemscope itemtype": "http://schema.org/Offer"}):
              prix = repo.find("span", {"itemprop": "priceCurrency"})
              prix = prix.text if prix else ""
              writer.writerow([prix])
  </code></pre>
  
  <p>I get this error : </p>
  
  <pre><code>Traceback (most recent call last):
  File "nv.py", line 14, in &lt;module&gt;
  for repo in repo.find_all("li", attrs={"itemscope itemtype": "http://schema.org/Offer"}):
  AttributeError: 'NoneType' object has no attribute 'find_all'
  </code></pre>