class_docstr: A class to verify ssl sockets for RFC6960/RFC6961. This can be used
  when using direct validation of OCSP responses and certificate revocations.
  
  @see https://datatracker.ietf.org/doc/html/rfc6960
  @see https://datatracker.ietf.org/doc/html/rfc6961
docstr: Checks the validity of an ocsp server for an issuer
docstr_tok: ["Checks","the","validity","of","an","ocsp","server","for","an","issuer"]
code: def check_certificate(self, server, cert, issuer_url):
      """Checks the validity of an ocsp server for an issuer"""
  
      r = requests.get(issuer_url)
      if not r.ok:
          raise ConnectionError("failed to fetch issuer certificate")
      der = r.content
      issuer_cert = self._bin2ascii(der)
  
      ocsp_url = self.build_certificate_url(server, cert, issuer_cert)
  
      # HTTP 1.1 mandates the addition of the Host header in ocsp responses
      header = {
          "Host": urlparse(ocsp_url).netloc,
          "Content-Type": "application/ocsp-request",
      }
      r = requests.get(ocsp_url, headers=header)
      if not r.ok:
          raise ConnectionError("failed to fetch ocsp certificate")
      return _check_certificate(issuer_cert, r.content, True)
  
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 7 for calling the OCSPVerifier obj's underlying member method code with example usage: obj.check_certificate(server, cert, issuer_url) and returns: _check_certificate