code: def ocsp_staple_verifier(con, ocsp_bytes, expected=None):
      """An implemention of a function for set_ocsp_client_callback in PyOpenSSL.
  
      This function validates that the provide ocsp_bytes response is valid,
      and matches the expected, stapled responses.
      """
      if ocsp_bytes in [b"", None]:
          raise ConnectionError("no ocsp response present")
  
      issuer_cert = None
      peer_cert = con.get_peer_certificate().to_cryptography()
      for c in con.get_peer_cert_chain():
          cert = c.to_cryptography()
          if cert.subject == peer_cert.issuer:
              issuer_cert = cert
              break
  
      if issuer_cert is None:
          raise ConnectionError(
              "no matching issuer cert found in certificate chain"
          )
  
      if expected is not None:
          e = x509.load_pem_x509_certificate(expected)
          if peer_cert != e:
              raise ConnectionError(
                  "received and expected certificates do not match"
              )
  
      return _check_certificate(issuer_cert, ocsp_bytes)
  
imports: import base64
  import datetime
  import ssl
  from urllib.parse import urljoin, urlparse
  import cryptography.hazmat.primitives.hashes
  import requests
  from cryptography import hazmat, x509
  from cryptography.exceptions import InvalidSignature
  from cryptography.hazmat import backends
  from cryptography.hazmat.primitives.asymmetric.dsa import DSAPublicKey
  from cryptography.hazmat.primitives.asymmetric.ec import ECDSA, EllipticCurvePublicKey
  from cryptography.hazmat.primitives.asymmetric.padding import PKCS1v15
  from cryptography.hazmat.primitives.asymmetric.rsa import RSAPublicKey
  from cryptography.hazmat.primitives.hashes import SHA1, Hash
  from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat
  from cryptography.x509 import ocsp
  from redis.exceptions import AuthorizationError, ConnectionError
label_desc: Use image node_id 5 for calling a global function with example usage: ocsp_staple_verifier(con, ocsp_bytes, expected) and returns: _check_certificate