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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 partition(self, id_):
 """Get a partition by the id number. Arguments: id_ -- a partition id value Returns: A partitions.Partition object Throws: a Sqlalchemy exception if the partition either does not exist or is not unique Because this method works on the bundle, the id_ ( without version information ) is equivalent to the vid ( with version information ) """

        from ..orm import Partition as OrmPartition
        from sqlalchemy import or_
        from ..identity import PartialPartitionName

        if isinstance(id_, PartitionIdentity):
            id_ = id_.id_
        elif isinstance(id_, PartialPartitionName):
            id_ = id_.promote(self.bundle.identity.name)

        session = self.bundle.dataset._database.session
        q = session\
            .query(OrmPartition)\
            .filter(OrmPartition.d_vid == self.bundle.dataset.vid)\
            .filter(or_(OrmPartition.id == str(id_).encode('ascii'),
                        OrmPartition.vid == str(id_).encode('ascii')))

        try:
            orm_partition = q.one()
            return self.bundle.wrap_partition(orm_partition)
        except NoResultFound:
            orm_partition = None

        if not orm_partition:
            q = session\
                .query(OrmPartition)\
                .filter(OrmPartition.d_vid == self.bundle.dataset.vid)\
                .filter(OrmPartition.name == str(id_).encode('ascii'))

            try:
                orm_partition = q.one()
                return self.bundle.wrap_partition(orm_partition)
            except NoResultFound:
                orm_partition = None

        return orm_partition