Can someone explains __all__ in Python?

The variable python __all__ is a list of public objects of that module, as interpreted by import *. This variable overrides the default of hiding everything that begins with an underscore.

In other words, python __all__ is a list of strings defining what symbols in a module will be exported when from import * is used on the module.

For example, the below-mentioned code saved as foo.py explicitly exports the symbols bar and baz:

__all__ = ['bar', 'baz']

waz = 5

bar = 10

def baz():

return 'baz'

So, the two symbols bar and baz can be imported like follows:

from foo import *

print(bar)

print(baz)

# The following will produce an exception, as "waz" is not exported by the module

print(waz)

So, if the above part of the code which contains python __all__ is commented out, then this code will be executed to completion, as the default behavior of import * is to import all symbols that do not begin with an underscore, from the given namespace.