In Python, "__all__" is a special variable that is commonly used in libraries.
"__all__" should be near the top of a script before any imports are performed and before defining any classes, variables, or functions. When the library is imported, "__all__" acts like an index of importable objects within the library. In other words, this variable lists public objects. So, running "from LIBRARY import *" will only import the objects listed in the "__all__" variable.
__all__ = [
'FUNCTION1',
'FUNCTION2',
'FUNCTION3',
]
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