Understanding Python's Import Engine

[snippsat]

example will be the package_name at top level,so you most import from example.
Let say b.py is:

def foo():
    return 42

Import test.

E:\div_code
λ ptpython
>>> import example.test.a.b
>>> example.test.a.b.foo()
42

>>> # Using from
>>> from example.test.a import b
>>> b.foo()
42

For this to work most example folder with sub-folder be in sys.path of Python version used eg i use Python 3.7 here.