code: def partition(self, id_):
          
          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
docs: 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 )