If I am using pythonrc.py & 456.py files, when does the hou module get imported in relationship to these?

I know that pythonrc.py loads before 456.py.

Cheers,
Rob

Further to this …

If in the pythonrc.py file, I have the line
import os
my understanding is that it imports the os module into Houdini.

However, when I run another module that uses os, do I need to put the import os statement in that other file?