sqlachemy.orm.properties __all__ changed when import

Question

Sqlalchemy verison is: 1.3.17

If i do the following in the interactive terminal:

from sqlalchemy.orm import properties

the __all__ attribute of that module will have the value of

['ColumnProperty', 'CompositeProperty', 'ConcreteInheritedProperty', 'SynonymProperty', 'ComparableProperty', 'RelationshipProperty'].

But in the module the __all__ defined is:

__all__ = ["ColumnProperty"]

and there's no code change the __all__ variable in that module, this is so magic and strange, can someone help explain why this is happening?