my_project:
    - package_1
       - my_package_1_class_1.py
       - my_package_1_class_2.py
       - my_package_1_class_3.py

    - package_2
       - my_package_2_class_1.py
       - my_package_2_class_2.py
       - my_package_2_class_3.py
       - my_package_2_class_4.py

    - package_3
       - my_package_3_class_1.py
       - my_package_3_class_2.py

    - test
       - test_my_package_1_class_1.py
       - test_my_package_1_class_2.py
       - test_my_package_1_class_3.py
       - test_my_package_2_class_1.py
       - test_my_package_2_class_2.py
       - test_my_package_2_class_3.py
       - test_my_package_2_class_4.py
       - test_my_package_3_class_1.py
       - test_my_package_3_class_2.py

project/
    package_1/
        __init__.py
        package_1_class_1.py
        package_1_class_2.py
        package_1_class_3.py
        tests/
            __init__.py
            test_package_1_class_1.py
            test_package_1_class_2.py
            test_package_1_class_3.py
    package_2/
        package_2_class_1.py
        package_2_class_2.py
        package_2_class_3.py
        package_2_class_4.py
        tests/
            __init__.py
            test_package_2_class_1.py
            test_package_2_class_2.py
            test_package_2_class_3.py
            test_package_2_class_4.py
    package_3/
        __init__.py
        package_3_class_1.py
        package_3_class_2.py
        tests/
            __init__.py
            test_package_3_class_1.py
            test_package_3_class_2.py
    setup.py
    ...