How to make a tool changer move to home

static int sendMdiCommand(int n)
{
EMC_TASK_PLAN_EXECUTE emc_task_plan_execute_msg;

if (updateStatus()) {
return -1;
}

if (!halui_sent_mdi) {
// There is currently no MDI command from halui executing, we're
// currently starting the first one. Record what the Task mode is,
// so we can restore it when all the MDI commands finish.
halui_old_mode = emcStatus->task.mode;
}

// switch to MDI mode if needed
if (emcStatus->task.mode != EMC_TASK_MODE_MDI) {
if (sendMdi() != 0) {
rtapi_print("halui: %s: failed to Set Mode MDI\n", __func__);
return -1;
}
if (updateStatus() != 0) {
rtapi_print("halui: %s: failed to update status\n", __func__);
return -1;
}
if (emcStatus->task.mode != EMC_TASK_MODE_MDI) {
rtapi_print("halui: %s: switched mode, but got %d instead of mdi\n", __func__, emcStatus->task.mode);
return -1;
}
}
rtapi_strxcpy(emc_task_plan_execute_msg.command, mdi_commands[n]);
if (emcCommandSend(emc_task_plan_execute_msg)) {
rtapi_print("halui: %s: failed to send mdi command %d\n", __func__, n);
return -1;
}
halui_sent_mdi = 1;
return 0;
}

def home_all_joints(event=None):
if not manual_ok(): return
ensure_mode(linuxcnc.MODE_MANUAL)
isHomed = all_homed()
doHoming=True
if isHomed:
doHoming=prompt_areyousure(_("Warning"),_("Joint is already homed, are you sure you want to re-home?"))
if doHoming:
go_home(-1)