I have added a git submodule in my project. Now all the imports in that submodule are broken because I have to use the full path of import. 
For example, if the structure is like this: 
Myproject:
- submodule_project:
-- package1:
--- code1.py
-- package2:
--- code2.py  
Now, in code1.py there is from package2 import code2. It tells me that package2 is unresolved reference. It is only resolved if I change it to from submodule_project.package2 import code2.
I don't want this because I don't want to change anything in the submodule. I just added it to use some of its packages in my project and to get regularly updated whenever its developers update it.
If you want package2 to be a top-level importable package its parent directory (submodule_project in your case) has to be in sys.path. There are many way to do it: sys.path.append(), sys.path.insert(), PYTHONPATH environment variable.
Or may be you don't want to have the code as a submodule at all. It doesn't make sense to have a submodule if the code in the submodule uses absolute import instead of relative (from ..package2 import code2). May be the package should be installed in site-packages (global or in a virtual environment) but not attached to the project as a submodule.
python importing level 2 packages