Limitation of the current Class inheritance

[thomassajot]

When adding the DataMixin class (PR: #14), the inheritence of most of the classes in the repo have not been set properly.
An failing example:

import ipywidgets
from jupyter_innotater.data import Innotation, TextInnotation, BoundingBoxInnotation

class ButtonInnotationExtended(Innotation):
    requires_data = False

    def __init__(self, icon, description, on_click=None, **kwargs):
        self.icon = icon
        self.description = description
        self.on_click_callback = on_click
        super().__init__(**kwargs)

    def on_click(self, callback, remove=False):
        self.button.on_click(callback, remove)

    def _create_widget(self):
        if not hasattr(self, "button"):
            self.button = ipywidgets.Button(description=self.description, layout=self.layout, icon=self.icon)
            if self.on_click_callback is not None:
                self.button.on_click(self.on_click_callback)
            return self.button
        return self.button

    def update_ui(self, uindex):
        pass

    def update_data(self, uindex):
        pass

Calling ButtonInnotationExtended(description='save', on_click=None, icon='save') would fail with the exception TypeError: object.__init__() takes exactly one argument (the instance to initialize).

After reading this very good blog posts: Python’s super() considered super! and Cooperative multiple-inheritance paradigm in python, it seems that there is a better way to propagate unknown arguments through the class inheritance tree.

[danlester]

@thomassajot Thank you for making this issue.

I won't have a chance to have a proper look for a while. If you do get a chance to put together a PR then of course that would really help.

I think I have seen those articles in another context more recently actually, so it all makes some sense.

Dan