About dsRegisterHdcpStatusCallback

In RDK, I saw below comment:

* @note Application should install at most one callback function per handle.

dsError_t dsRegisterHdcpStatusCallback (int handle, dsHDCPStatusCallback_t cb);

But it is limited by define HAS_HDCP_CALLBACK.

And using NULL handle in server - dsVideoPort.c

#ifdef HAS_HDCP_CALLBACK
dsRegisterHdcpStatusCallback(NULL,_dsHdcpCallback);
#endif

How do i implement it ?

Or it's not a necessary DeviceSettingHalAPI ?