code: def test_del_slice(sphere):
      multi = MultiBlock({f"{i}": sphere for i in range(10)})
      del multi[0:10:2]
      assert len(multi) == 5
      assert all(f"{i}" in multi.keys() for i in range(1, 10, 2))
  
      multi = MultiBlock({f"{i}": sphere for i in range(10)})
      del multi[5:2:-1]
      assert len(multi) == 7
      assert all(f"{i}" in multi.keys() for i in [0, 1, 2, 6, 7, 8, 9])
  
imports: import pathlib
  import platform
  import weakref
  import numpy
  import pytest
  import vtk
  import pyvista
  from pyvista import ImageData, MultiBlock, PolyData, RectilinearGrid, StructuredGrid, examples
label_desc: Use image node_id 10 for calling a global function with example usage: test_del_slice(sphere) without return types