Python hashable


`__hash()` make to be
- key of [Python Dictionary](https://texonom.com/python-dictionary-8a83fd91142347adbf25bcdf8a87cf09) 
- member of [python Set](https://texonom.com/python-set-d9871b9a760b4972b22224cea4785396) 
Almost python immutable is hashable object









