class_docstr: This class just creates slice objects for image resampling
  
  It only has a __getitem__ method that returns its argument.
  
  XXX Wouldn't need this if there was a way
  XXX to do this
  XXX subsample(img, [::2,::3,10:1:-1])
  XXX
  XXX Could be something like this Subsample(img)[::2,::3,10:1:-1]
code: def __getitem__(self, index):
      return index
  
imports: import warnings
  from copy import copy
  from itertools import chain
  import numpy
  from nibabel.onetime import auto_attr
  from ..reference.array_coords import ArrayCoordMap
  from ..reference.coordinate_map import AffineTransform, CoordinateSystem, input_axis_index
label_desc: Use image node_id 1 for calling the SliceMaker obj's underlying member method code with example usage: obj.__getitem__(index) and returns: index