How to translate data item (void pointer) in linked list from c++ to python with SIP?

I am translating a linked list with Python SIP.

I have a generic open type structure - a struct to hold the data in bytes (const unsigned char *) and the number of octets. When I pass this data to the void pointer 'holding' the data of the list in python I get: TypeError: an integer is required

I tried passing id(dataFirstNode) but its not the address of dataFirstNode.

The SIP wrapper should ask for the address of a void pointer object not an int?! The generated SIP code looks fine to me, but I could have missed something (not an expert).

How could I solve this without changing the c++ code?

The linked list in c++ is working fine:

// datatype for first NodeDataType dataFirstNode;
int rawData = 11;
dataFirstNode.numocts = sizeof(rawData);
dataFirstNode.data = reinterpret_cast<const unsigned char *>(&rawData);

// node to be passed to testList
ListNode firstNode;
firstNode.data = &dataFirstNode;
firstNode.next = nullptr;
firstNode.prev = nullptr;

The equivalent in python:

// datatype for first Node
dataFirstNode = DataType()
rawData = 12
size = ctypes.sizeof(ctypes.c_int)
dataFirstNode.data = rawData.to_bytes(size, sys.byteorder)
dataFirstNode.numocts = size


# node to be passed to testList
firstNode = ListNode()
firstNode.data = dataFirstNode  # Error here!
firstNode.next = None
firstNode.prev = None

Excerpt of code from the sip file:

struct ListNode {

%TypeHeaderCode
#include ...
%End

   void* data;
   struct ListNode* next;
   struct ListNode* prev;
};


struct DataType {          /* generic open type data structure */

%TypeHeaderCode
#include ...
%End

   const unsigned char* data;
   int   numocts;
};

Does someone have an idea?

Thanx

Johnny