Without seeing your code, and the actual exception and error message you
are getting, we would be guessing.
My guess is that you have a typo in the subclass name, or you are not
using the fully qualified name, or you are trying to use the subclass
before you have defined it.
Why are you using
importlib.import_module instead of
It might help if you read these:
and remember to post your code and the exception as text, not as
screenshots or images. You can format the code using the
</> button in
the fancy text editor widget, or if replying by email you can surround
it by three backticks:
backticks must be on a line of their own
code goes here