The __init__.py file serves to declare and initialize a module package; Python automatically runs its code the first time you import through a directory in a process. Its assigned variables become the attributes of the module object created in memory to correspond to that directory. It is also not optional—you can’t import through a directory with package syntax unless it contains this file.

Use the from statement with a package to copy names out of the package directly, or use the as extension with the import statement to rename the path to a shorter synonym. In both cases, the path is listed in only one place, in the from or import statement.