implicit-namespace-package (INP001)
Derived from the flake8-no-pep420 linter.
What it does
Checks for packages that are missing an __init__.py file.
Why is this bad?
Python packages are directories that contain a file named __init__.py.
The existence of this file indicates that the directory is a Python
package, and so it can be imported the same way a module can be
imported.
Directories that lack an __init__.py file can still be imported, but
they're indicative of a special kind of package, known as a "namespace
package" (see: PEP 420).
Namespace packages are less widely used, so a package that lacks an
__init__.py file is typically meant to be a regular package, and
the absence of the __init__.py file is probably an oversight.