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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _calendar_classes_for_occurrence(self, occurrence):
 """ Return css classes to be used in admin calendar JSON """

        classes = [slugify(occurrence.event.polymorphic_ctype.name)]

        # Add a class name for the type of event.
        if occurrence.is_all_day:
            classes.append('is-all-day')
        if occurrence.is_protected_from_regeneration:
            classes.append('is-user-modified')
        if occurrence.is_cancelled:
            classes.append('is-cancelled')

        # if an event isn't published or does not have show_in_calendar ticked,
        # indicate that it is hidden
        if not occurrence.event.show_in_calendar:
            classes.append('do-not-show-in-calendar')

        # Prefix class names with "fcc-" (full calendar class).
        classes = ['fcc-%s' % class_ for class_ in classes]

        return classes