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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 anime(self, item_id):
 """ The function to retrieve an anime's details. :param int item_id: the anime's ID :return: dict or None :rtype: dict or NoneType """

        query_string = """\
            query ($id: Int) {
                Media(id: $id, type: ANIME) {
                    title {
                        romaji
                        english
                    }
                    startDate {
                        year
                        month
                        day
                    }
                    endDate {
                        year
                        month
                        day
                    }
                    coverImage {
                        large
                    }
                    bannerImage
                    format
                    status
                    episodes
                    season
                    description
                    averageScore
                    meanScore
                    genres
                    synonyms
                    nextAiringEpisode {
                        airingAt
                        timeUntilAiring
                        episode
                    }
                }
            }
        """
        vars = {"id": item_id}
        r = requests.post(self.settings['apiurl'],
                         headers=self.settings['header'],
                         json={'query': query_string, 'variables': vars})
        jsd = r.text

        try:
            jsd = json.loads(jsd)
        except ValueError:
            return None
        else:
            return jsd