def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int)) 

def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int)) 

def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int)) 

def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int)) 

def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int)) 

def assertCRL(self, crl, certs=None, signer=None, expires=86400, algorithm=None, encoding=Encoding.PEM,
                  idp=None, extensions=None, crl_number=0, skip_authority_key_identifier=False):
        certs = certs or []
        signer = signer or self.cas['child']
        algorithm = algorithm or ca_settings.CA_DIGEST_ALGORITHM
        extensions = extensions or []
        expires = datetime.utcnow() + timedelta(seconds=expires)

        if idp is not None:  # pragma: no branch
            extensions.append(idp)
        extensions.append(x509.Extension(
            value=x509.CRLNumber(crl_number=crl_number),
            critical=False, oid=ExtensionOID.CRL_NUMBER
        ))
        if not skip_authority_key_identifier:
            extensions.append(signer.authority_key_identifier.as_extension())

        if encoding == Encoding.PEM:
            crl = x509.load_pem_x509_crl(crl, default_backend())
        else:
            crl = x509.load_der_x509_crl(crl, default_backend())

        self.assertIsInstance(crl.signature_hash_algorithm, type(algorithm))
        self.assertTrue(crl.is_signature_valid(signer.x509.public_key()))
        self.assertEqual(crl.issuer, signer.x509.subject)
        self.assertEqual(crl.last_update, datetime.utcnow())
        self.assertEqual(crl.next_update, expires)
        self.assertCountEqual(list(crl.extensions), extensions)

        entries = {e.serial_number: e for e in crl}
        expected = {c.x509.serial_number: c for c in certs}
        self.assertCountEqual(entries, expected)
        for serial, entry in entries.items():
            self.assertEqual(entry.revocation_date, datetime.utcnow())
            self.assertEqual(list(entry.extensions), []) 

def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int)) 

def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int)) 

def _decode_crl_number(backend, ext):
    asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
    asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
    return x509.CRLNumber(_asn1_integer_to_int(backend, asn1_int))