docs: def split_pem(s):
      """
      Split PEM objects. Useful to process concatenated certificates.
      """
      pem_strings = []
      while s != b"":
          start_idx = s.find(b"-----BEGIN")
          if start_idx == -1:
              break
          end_idx = s.find(b"-----END")
          end_idx = s.find(b"\n", end_idx) + 1
          pem_strings.append(s[start_idx:end_idx])
          s = s[end_idx:]
      return pem_strings