code: def center_shift(self):
      return self._center_shift
  
imports: import numpy
  from ...None import opcodes
  from ...core import OutputType, recursive_tile
  from ...core.operand import OperandStage
  from ...serialization.serializables import KeyField, Int32Field, BoolField
  from ...tensor.array_utils import as_same_device, device, cp, sparse
  from ...tensor.core import TensorOrder
  from ...utils import has_unknown_shape
  from ..operands import LearnOperand, LearnOperandMixin
  from ._k_means_common import _execute_merge_update, _relocate_empty_clusters
  from ._k_means_elkan import init_bounds_dense, init_bounds_sparse, update_chunk_dense, update_chunk_sparse
  from ._k_means_fast import update_center, update_upper_lower_bounds
label_desc: Use image node_id 4 for calling the KMeansElkanPostprocess obj's underlying member method code with example usage: obj.center_shift() and returns: self