Why do modules in Python create __init__.py files?

The __init__.py file in Python serves to designate a directory as a package. Without this file, Python will not consider the folder as a package, and importing modules from it will be impossible or difficult.

Additionally, in __init__.py, you can perform package initialization, such as importing submodules for convenience, defining variables or functions that will be accessible upon package import.

Example structure:

mypackage/
  __init__.py
  module1.py
  module2.py

If you write in __init__.py:

from .module1 import func1

then you can import func1 directly:

from mypackage import func1

Thus, __init__.py acts as an index and initializer for the package.