code: def __init__(self, *args, **kwargs):
      super().__init__(*args, **kwargs)
      self._index_skip = False
  
imports: import sys
  import numpy
  import pandas
  from ..core import Dataset, NdOverlay, util
  from ..streams import Lasso, Selection1D, SelectionXY
  from ..util.transform import dim
  from .annotation import HSpan, VSpan
label_desc: Use image node_id 1 to create a new SelectionIndexExpr object  with example: obj = SelectionIndexExpr()