code: def _check_slicer(
      sliceobj, arr, fobj, offset, order, heuristic=threshold_heuristic
  ):
      new_slice = fileslice(
          fobj, sliceobj, arr.shape, arr.dtype, offset, order, heuristic
      )
      assert_array_equal(arr[sliceobj], new_slice)
  
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 22 for calling a global function with example usage: _check_slicer(sliceobj, arr, fobj, offset, order, heuristic) without return types