Just to make sure, the first two steps are working ?
Maybe it has to do with the fact the "training" step specifies a docker image, could you try to remove it and check?
BTW: A few pointers
The return_values is used to specify multiple returned objects stored individually, not the type of the object. If there is a single object, no need to specify
The parents argument is optional, the pipeline components optimizes execution based on inputs, for example in your code, all pipeline components will be running in parallel, because they do not rely on the return value of one another, unless of course if you specify " parents " 🙂