code: def add_other_cert(self, cert):
          
  
          if not isinstance(cert, x509.Certificate):
              if not isinstance(cert, byte_cls):
                  raise TypeError(pretty_message(
                      '''
                      cert must be a byte string or an instance of
                      asn1crypto.x509.Certificate, not %s
                      ''',
                      type_name(cert)
                  ))
              if pem.detect(cert):
                  _, _, cert = pem.unarmor(cert)
              cert = x509.Certificate.load(cert)
  
          hashable = cert.subject.hashable
          if hashable not in self._subject_map:
              self._subject_map[hashable] = []
  
          # Don't add the cert if we already have it
          else:
              serial_number = cert.serial_number
              for existing_cert in self._subject_map[hashable]:
                  if existing_cert.serial_number == serial_number:
                      return False
  
          self._subject_map[hashable].append(cert)
          if cert.key_identifier:
              self._key_identifier_map[cert.key_identifier] = cert
          else:
              self._key_identifier_map[cert.public_key.sha1] = cert
  
          return True
docs: Allows adding an "other" cert that is obtained from doing revocation
          check via OCSP or CRL, or some other method
  
          :param cert:
              An asn1crypto.x509.Certificate object or a byte string of a DER or
              PEM-encoded certificate
  
          :return:
              A boolean indicating if the certificate was added - will return
              False if the certificate was already present