The __all__ property of a module is used to define the list of names that will be imported when performing a wildcard import of this
module, i.e. when from mymodule import * is used.
In the following example:
# mymodule.py
def foo(): ...
def bar(): ...
__all__ = ["foo"]
Executing from mymodule import * from a different module will only import foo.
This list can only reference defined names, otherwise an AttributeError will be raised when the module is imported.
Code examples
Noncompliant code example
from mymodule import my_func
__all__ = ["unknown_func"] # Noncompliant: "unknown_func" is undefined
Compliant solution
from mymodule import my_func
__all__ = ["my_func"]
