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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_thumbnails(self, size=None):
 """ Returns this Item Thumbnails. Thumbnails are not supported on SharePoint Server 2016. :param size: request only the specified size: ej: "small", Custom 300x400 px: "c300x400", Crop: "c300x400_Crop" :return: Thumbnail Data :rtype: dict """

        if not self.object_id:
            return []

        url = self.build_url(
            self._endpoints.get('thumbnails').format(id=self.object_id))

        params = {}
        if size is not None:
            params['select'] = size

        response = self.con.get(url, params=params)
        if not response:
            return []

        data = response.json()

        if not self.thumbnails or size is None:
            self.thumbnails = data

        return data