@classmethod
def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
    usage = tok.get_uint8()
    selector = tok.get_uint8()
    mtype = tok.get_uint8()
    cert_chunks = []
    while 1:
        t = tok.get().unescape()
        if t.is_eol_or_eof():
            break
        if (not t.is_identifier()):
            raise dns.exception.SyntaxError
        cert_chunks.append(t.value.encode())
    cert = b''.join(cert_chunks)
    cert = binascii.unhexlify(cert)
    return cls(rdclass, rdtype, usage, selector, mtype, cert)
@classmethod
def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
    usage = tok.get_uint8()
    selector = tok.get_uint8()
    mtype = tok.get_uint8()
    cert_chunks = []
    while 1:
        t = tok.get().unescape()
        if t.is_eol_or_eof():
            break
        if (not t.is_identifier()):
            raise dns.exception.SyntaxError
        cert_chunks.append(t.value.encode())
    cert = b.join(cert_chunks)
    cert = binascii.unhexlify(cert)
    return cls(rdclass, rdtype, usage, selector, mtype, cert)