modules

https://docs.python.org/3/tutorial/modules.html

The Module Search Path

sys.path is initialized from these locations:

• The directory containing the input script (or the current directory when no file is specified).

• PYTHONPATH (a list of directory names, with the same syntax as the shell variable PATH).

• The installation-dependent default (by convention including a site-packages directory, handled by the site module).

The dir() Function

>>> a = [1, 2, 3, 4, 5]
>>> import fibo
>>> fib = fibo.fib
>>> dir()
['__builtins__', '__name__', 'a', 'fib', 'fibo', 'sys']

Packages

import sound.effects.echo

sound.effects.echo.echofilter(input, output, delay=0.7, atten=4)

from sound.effects import echo

Importing * From a Package

if a package’s __init__.py code defines a list named __all__, it is taken to be the list of module names that should be imported when from package import * is encountered.

__all__ = ["echo", "surround", "reverse"]

If __all__ is not defined, the statement from sound.effects import * does not import all submodules from the package sound.effects into the current namespace; it only ensures that the package sound.effects has been imported (possibly running any initialization code in __init__.py) and then imports whatever names are defined in the package. This includes any names defined (and submodules explicitly loaded) by __init__.py. It also includes any submodules of the package that were explicitly loaded by previous import statements