code: def _slices_for_len(L):
      # Example slices for a dimension of length L
      if L == 0:
          raise ValueError("Need length > 0")
      sdefs = [0, L // 2, L - 1, -1, slice(None), slice(L - 1)]
      if L > 1:
          sdefs += [
              -2,
              slice(1, L - 1),
              slice(1, L - 1, 2),
              slice(L - 1, 1, -1),
              slice(L - 1, 1, -2),
          ]
      return tuple(sdefs)
  
imports: import time
  from functools import partial
  from io import BytesIO
  from itertools import product
  from threading import Lock, Thread
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from ..fileslice import _positive_slice, _simple_fileslice, calc_slicedefs, canonical_slicers, fileslice, fill_slicer, is_fancy, optimize_read_slicers, optimize_slicer, predict_shape, read_segments, slice2len, slice2outax, slicers2segments, strided_scalar, threshold_heuristic
label_desc: Use image node_id 5 for calling a global function with example usage: _slices_for_len(L) and returns: tuple