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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 read(self):
 """ Read the targets value """

        cursor = self.get_collection().find(
            {
                '_id': {'$in': self._document_ids},
                self._field: {'$exists': True}
            },
            {self._field: True}
        )

        return {doc['_id']: doc[self._field] for doc in cursor}