How to use the kazoo.protocol.serialization.int_struct.unpack function in kazoo

def _read_header(self, timeout):
        b = self._read(4, timeout)
        length = int_struct.unpack(b)[0]
        b = self._read(length, timeout)
        header, offset = ReplyHeader.deserialize(b, 0)
        return header, b, offset

if xid:
            header, buffer, offset = self._read_header(timeout)
            if header.xid != xid:
                raise RuntimeError('xids do not match, expected %r received %r',
                                   xid, header.xid)
            if header.zxid > 0:
                zxid = header.zxid
            if header.err:
                callback_exception = EXCEPTIONS[header.err]()
                self.logger.debug(
                    'Received error(xid=%s) %r', xid, callback_exception)
                raise callback_exception
            return zxid

        msg = self._read(4, timeout)
        length = int_struct.unpack(msg)[0]
        msg = self._read(length, timeout)

        if hasattr(request, 'deserialize'):
            try:
                obj, _ = request.deserialize(msg, 0)
            except Exception:
                self.logger.exception("Exception raised during deserialization"
                                      " of request: %s", request)

                # raise ConnectionDropped so connect loop will retry
                raise ConnectionDropped('invalid server response')
            self.logger.log(BLATHER, 'Read response %s', obj)
            return obj, zxid

        return zxid

if xid:
            header, buffer, offset = self._read_header(timeout)
            if header.xid != xid:
                raise RuntimeError('xids do not match, expected %r received %r',
                                   xid, header.xid)
            if header.zxid > 0:
                zxid = header.zxid
            if header.err:
                callback_exception = EXCEPTIONS[header.err]()
                self.logger.debug(
                    'Received error(xid=%s) %r', xid, callback_exception)
                raise callback_exception
            return zxid

        msg = self._read(4, timeout)
        length = int_struct.unpack(msg)[0]
        msg = self._read(length, timeout)

        if hasattr(request, 'deserialize'):
            try:
                obj, _ = request.deserialize(msg, 0)
            except Exception:
                self.logger.exception("Exception raised during deserialization"
                                      " of request: %s", request)

                # raise ConnectionDropped so connect loop will retry
                raise ConnectionDropped('invalid server response')
            self.logger.log(BLATHER, 'Read response %s', obj)
            return obj, zxid

        return zxid

if xid:
            header, buffer, offset = self._read_header(timeout)
            if header.xid != xid:
                raise RuntimeError('xids do not match, expected %r '
                                   'received %r', xid, header.xid)
            if header.zxid > 0:
                zxid = header.zxid
            if header.err:
                callback_exception = EXCEPTIONS[header.err]()
                self.logger.debug(
                    'Received error(xid=%s) %r', xid, callback_exception)
                raise callback_exception
            return zxid

        msg = self._read(4, timeout)
        length = int_struct.unpack(msg)[0]
        msg = self._read(length, timeout)

        if hasattr(request, 'deserialize'):
            try:
                obj, _ = request.deserialize(msg, 0)
            except Exception:
                self.logger.exception(
                    "Exception raised during deserialization "
                    "of request: %s", request)

                # raise ConnectionDropped so connect loop will retry
                raise ConnectionDropped('invalid server response')
            self.logger.log(BLATHER, 'Read response %s', obj)
            return obj, zxid

        return zxid

def _read_header(self, timeout):
        b = self._read(4, timeout)
        length = int_struct.unpack(b)[0]
        b = self._read(length, timeout)
        header, offset = ReplyHeader.deserialize(b, 0)
        return header, b, offset