'This extension indicates the issuer of the certificate in question,
and is used in indirect CRLs. CRL entries without this extension are
for certificates issued from the last seen issuer.
:return:
None or an x509.GeneralNames object'

@property
def certificate_issuer_value(self):

    if (self._processed_extensions is False):
        self._set_extensions()
    return self._certificate_issuer_value
