# AddCustomTerminationCallback from vtkStreamTracer in Python

**URL:** https://discourse.vtk.org/t/addcustomterminationcallback-from-vtkstreamtracer-in-python/7986
**Category:** Support
**Tags:** python
**Created:** [March 5, 2022, 10:14pm UTC](https://discourse.vtk.org/t/addcustomterminationcallback-from-vtkstreamtracer-in-python/7986 "2022-03-05T22:14:19Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![MatthewFlamm](https://discourse.vtk.org/user_avatar/discourse.vtk.org/matthewflamm/32/4350_2.png) [@MatthewFlamm](https://discourse.vtk.org/u/MatthewFlamm)
#### Post date: [March 5, 2022, 10:14pm UTC](https://discourse.vtk.org/t/addcustomterminationcallback-from-vtkstreamtracer-in-python/7986/1 "2022-03-05T22:14:19Z")

</div>

I was trying to see if the AddCustomTerminationCallback method could be used in Python, but it doesn’t seem to be exposed. Is there a way to access this functionality?

```auto
from vtkmodules.vtkFiltersFlowPaths import vtkStreamTracer
assert "AddCustomTerminationCallback" in dir(vtkStreamTracer())

```

This code raises an `AssertionError`.