docs: def certificate(self, value):
          """
          An asn1crypto.x509.Certificate or oscrypto.asymmetric.Certificate object
          of the certificate the response is about.
          """
  
          if value is not None:
              is_oscrypto = isinstance(value, asymmetric.Certificate)
              if not is_oscrypto and not isinstance(value, x509.Certificate):
                  raise TypeError(_pretty_message(
                      '''
                      certificate must be an instance of asn1crypto.x509.Certificate
                      or oscrypto.asymmetric.Certificate, not %s
                      ''',
                      _type_name(value)
                  ))
  
              if is_oscrypto:
                  value = value.asn1
  
          self._certificate = value