Sorry, I did not read your post carefully enough. I now see you are using Panda3D.direct.showbase.ShowBase as the module name.
It is not standard to configure Panda3D this way. I strongly recommend that you instead place the Panda3D directory on your python module search path in your IDE’s configuration, so that you can import it the usual way, via “direct.showbase.ShowBase”.
That said, if you really wanted to use this nonstandard import structure, you would need to ensure that there is an empty init.py file inside the Panda3D directory, to make sure that it is recognised a valid Python package.