code: def create_temporary_ca_path(anchor_list, folder):
      
      # We should probably avoid writing duplicate anchors and also
      # check if they are all certs.
      try:
          if not os.path.isdir(folder):
              os.makedirs(folder)
      except:
          return None
      
      l = len(anchor_list)
      if l == 0:
          return None
      fmtstr = "%%0%sd.pem" % math.ceil(math.log(l, 10))
      i = 0
      try:
          for a in anchor_list:
              fname = os.path.join(folder, fmtstr % i)
              f = open(fname, "w")
              s = a.output(fmt="PEM")
              f.write(s)
              f.close()
              i += 1
      except:
          return None
  
      r,w,e=popen3(["c_rehash", folder])
      r.close(); w.close(); e.close()
  
      return l
docs: Create a CA path folder as defined in OpenSSL terminology, by
      storing all certificates in 'anchor_list' list in PEM format
      under provided 'folder' and then creating the associated links
      using the hash as usually done by c_rehash.
  
      Note that you can also include CRL in 'anchor_list'. In that
      case, they will also be stored under 'folder' and associated
      links will be created.
  
      In folder, the files are created with names of the form
      0...ZZ.pem. If you provide an empty list, folder will be created
      if it does not already exist, but that's all.
  
      The number of certificates written to folder is returned on
      success, None on error.