python git-submodule importing from other git-submodule - python-3.x

Question

Using Python 3.6
I did create multiple modules (like DBmanager or jsonParser etc which I use across multiple different python projects)
For simplicity: I have created a module, lets call it 'gitmodule03'.
Internally it is supposed to be using yet another module from github 'gitmodule01' for parsing data. I have added 'gitmodule01' to 'gitmodule03' by
'git submodule add http://git/gitmodule01'
Separatenly, I am developing my 'MainPackage' which will use directly 'gitmodule03' and 'gitmodule01' (among others). I've added them all to my main Program with
'git submodule add http://git/gitmodule01'
'git submodule add http://git/gitmodule02'
'git submodule add http://git/gitmodule03'
and my package looks like this:
.
└── MainPackage
├── modules
│   ├── __init__.py
│   ├── gitmodule01
│   │   ├── __init__.py
│   │   └── mymodule01.py
│   ├── gitmodule02
│   │   ├── __init__.py
│   │   └── mymodule02.py
│   ├── gitmodule03
│   │   ├── __init__.py
│   │   ├── mymodule03.py
│   │   └── gitmodule01
│   │   └──
│   └── mymodule04.py
└── myMainProgram.py
At this moment 'gitmodule03' is NOT importing 'gitmodule01' internally. I was hoping that importing it in main myMainProgram.py would propagate across submodules (which is not the case)
If my myMainProgram.py imports them all:
from modules.gitmodule01.mymodule01 import my01class
from modules.gitmodule02.mymodule02 import my02class
from modules.gitmodule03.mymodule03 import my03class
my03class() # will work
my02class() # is internally using 'my03class()' and will error out:
NameError: name 'my03class' is not defined
How can I design those so they can work independently as well as within bigger package, in clean, pythonic way ?
I would like to have those modules idependent so they won't have to use any hard coded sys.path() methods
Edit Test Cases:
1.
myMainProgram.py
sys.path.insert(0, "modules/gitmodule03/gitmodule01/")
from mymodule01 import my01class
from modules.gitmodule03.mymodule03 import my03class
my01class() #works
my03class() # NameError: name 'my01class' is not defined
2.
myMainProgram.py
from modules.gitmodule03.gitmodule01.mymodule01 import my01class
from modules.gitmodule03.mymodule03 import my03class
my01class() #works
my03class() # NameError: name 'my01class' is not defined
3.
mymodule03.py
from gitmodule01.mymodule01 import my01class
my01class() #works
myMainProgram.py
from modules.gitmodule01.mymodule01 import my01class
from modules.gitmodule03.mymodule03 import my03class
my03class() # ModuleNotFoundError: No module named 'gitmodule01'
4.
mymodule03.py
from .gitmodule01.mymodule01 import my01class
my01class() # ModuleNotFoundError: No module named '__main__.gitmodule01'; '__main__' is not a package
myMainProgram.py
from modules.gitmodule03.mymodule03 import my03class
my03class() # works
With Test Case #4 It looks like i could make myMainProgram.py work but i would have to break module on its own.

Answer 1

So far I could not find better option to have both working myMainProgram.py and mymodule03.py on its own.
At the moment I am checking name variable to see whenever module is working on its own or whenever it is run from other package:
mymodule03.py
if __name__ == '__main__':
from gitmodule01.mymodule01 import my01class
my01class() # works
else:
from .gitmodule01.mymodule01 import my01class
myMainProgram.py
from modules.gitmodule03.mymodule03 import my03class
my03class() # works