code: def test_multi_block_save_lines(tmpdir):
      radius = 1
      xr = np.random.default_rng().random(10)
      yr = np.random.default_rng().random(10)
      x = radius * np.sin(yr) * np.cos(xr)
      y = radius * np.sin(yr) * np.sin(xr)
      z = radius * np.cos(yr)
      xyz = np.stack((x, y, z), axis=1)
  
      poly = pv.lines_from_points(xyz, close=False)
      blocks = pv.MultiBlock()
      for _ in range(2):
          blocks.append(poly)
  
      path = tmpdir.mkdir("tmpdir")
      line_filename = str(path.join("lines.vtk"))
      block_filename = str(path.join("blocks.vtmb"))
      poly.save(line_filename)
      blocks.save(block_filename)
  
      poly_load = pv.read(line_filename)
      assert np.allclose(poly_load.points, poly.points)
  
      blocks_load = pv.read(block_filename)
      assert np.allclose(blocks_load[0].points, blocks[0].points)
  
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 31 for calling a global function with example usage: test_multi_block_save_lines(tmpdir) without return types