No module named '__main__.demo'; '__main__' is not a package python3

Question

If I execute main.py it works fine, the problem is when I execute demo2.py

|myPackage
   |subPackage
      demo.py
      demo2.py
   main.py

main.py

from ludikDriver.demo2 import demo2_print

demo2_print()

demo2.py

from .demo import demoprint

def demo2_print():
    print("demo2")
    demoprint()

demo2_print()

demo.py

def demoprint():
    print("demo")

Error: from .demo import demoprint

ModuleNotFoundError: No module named '__main__.demo'; '__main__' is not a package

Should I have __init__.py?

Answer 1

If you drop the ., it should work. demo2.py becomes:

from demo import demoprint # instead of `from .demo import demoprint`

def demo2_print():
    print("demo2")
    demoprint()

demo2_print()

Now you can run %run ludikDriver/demo2.py in ipython for instance and you get:

demo2
demo

For more details, the section "Imports" of this article might help.