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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 get(self, source, media, collection=None, start_date=None, days=None, query=None, years=None, genres=None, languages=None, countries=None, runtimes=None, ratings=None, certifications=None, networks=None, status=None, **kwargs):
 """Retrieve calendar items. The `all` calendar displays info for all shows airing during the specified period. The `my` calendar displays episodes for all shows that have been watched, collected, or watchlisted. :param source: Calendar source (`all` or `my`) :type source: str :param media: Media type (`dvd`, `movies` or `shows`) :type media: str :param collection: Collection type (`new`, `premieres`) :type collection: str or None :param start_date: Start date (defaults to today) :type start_date: datetime or None :param days: Number of days to display (defaults to `7`) :type days: int or None :param query: Search title or description. :type query: str or None :param years: Year or range of years (e.g. `2014`, or `2014-2016`) :type years: int or str or tuple or None :param genres: Genre slugs (e.g. `action`) :type genres: str or list of str or None :param languages: Language codes (e.g. `en`) :type languages: str or list of str or None :param countries: Country codes (e.g. `us`) :type countries: str or list of str or None :param runtimes: Runtime range in minutes (e.g. `30-90`) :type runtimes: str or tuple or None :param ratings: Rating range between `0` and `100` (e.g. `75-100`) :type ratings: str or tuple or None :param certifications: US Content Certification (e.g. `pg-13`, `tv-pg`) :type certifications: str or list of str or None :param networks: (TV) Network name (e.g. `HBO`) :type networks: str or list of str or None :param status: (TV) Show status (e.g. `returning series`, `in production`, ended`) :type status: str or list of str or None :return: Items :rtype: list of trakt.objects.video.Video """

        if source not in ['all', 'my']:
            raise ValueError('Unknown collection type: %s' % (source,))

        if media not in ['dvd', 'movies', 'shows']:
            raise ValueError('Unknown media type: %s' % (media,))

        # Default `start_date` to today when only `days` is provided
        if start_date is None and days:
            start_date = datetime.utcnow()

        # Request calendar collection
        response = self.http.get(
            '/calendars/%s/%s%s' % (
                source, media,
                ('/' + collection) if collection else ''
            ),
            params=[
                start_date.strftime('%Y-%m-%d') if start_date else None,
                days
            ],
            query={
                'query': query,
                'years': years,
                'genres': genres,

                'languages': languages,
                'countries': countries,
                'runtimes': runtimes,

                'ratings': ratings,
                'certifications': certifications,

                # TV
                'networks': networks,
                'status': status
            },
            **popitems(kwargs, [
                'authenticated',
                'validate_token'
            ])
        )

        # Parse response
        items = self.get_data(response, **kwargs)

        if isinstance(items, requests.Response):
            return items

        # Map items
        if media == 'shows':
            return SummaryMapper.episodes(
                self.client, items,
                parse_show=True
            )

        return SummaryMapper.movies(self.client, items)