Secret Recipes of the Python Ninja

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If __all__ is not defined in __init__.py, then import * only imports the modules within the specified package, not all sub-packages or their modules. For example, from video.formats import * only imports the video formats; the modules in the effects/ directory will not be included.

This is a best practice for Python programmers: as the Zen of Python (https://www.python.org/dev/peps/pep-0020/) states, explicit is better than implicit. Thus, importing a specific sub-module from a package is a good thing, whereas import * is frowned upon because of the possibility of variable name conflicts.

Packages have the __path__ attribute, which is rarely used. This attribute is a list that has the name of the directory where the package's ...