python packages

my_project
├── common
│   ├── a_utility.py
│   └── __init__.py
├── functionality_1
│   ├── create_something.py
│   └──__init__.py
├── functionality_2
│   ├── create_something_else.py
│   └──__init__.py
├── __init__.py
└── main.py


----------------------
create_something.py  |
----------------------

from my_project.common import a_utility
....


ImportError: No module named 'my_project.common'