def update_from_alpha(self):
        """Update the alpha value for entry and attribute."""

        ### update entry with scale value

        ## get alpha value from scale
        alpha_value = self.scale_map["alpha"].get()

        ## update the alpha entry with the alpha value we
        ## just retrieved
        self.entry_map["alpha"].set(alpha_value, False)

        ### set the alpha checkbutton to True (that is,
        ### since the user is editing the alpha, we assume
        ### it wants the alpha to be used; this also makes
        ### it so the alpha is updated in the preview rect
        ### in real time, which is useful)

        self.alpha_checkbutton.set(True, execute_command=False)

        ### finally update the color value from the
        ### rgb entry (also has side-effects of interest)
        self.update_from_rgb_entry()
Update the alpha value for entry and attribute.
nodezator/colorsman/editor/widgetop.py