code: def attached_partition(self):
          
          if self._attached_partition is None:
              part_mgr = self.manager.storage_group.manager.cpc.partitions
              part = part_mgr.resource_object(self.get_property('partition-uri'))
              self._attached_partition = part
          return self._attached_partition
docs: :class:`~zhmcclient.Partition`: The partition to which this virtual
          storage resource is attached.
  
          The returned partition object has only a minimal set of properties set
          ('object-id', 'object-uri', 'class', 'parent').
  
          Note that a virtual storage resource is always attached to a partition,
          as long as it exists.
  
          Authorization requirements:
  
          * Object-access permission to the storage group owning this
            virtual storage resource.
  
          Raises:
  
            :exc:`~zhmcclient.HTTPError`
            :exc:`~zhmcclient.ParseError`
            :exc:`~zhmcclient.AuthError`
            :exc:`~zhmcclient.ConnectionError`