code: def test_sparse_block():
      r1 = sps.rand(10, 5)
      r2 = sps.rand(10, 3)
      r3 = sps.rand(3, 5)
      r4 = sps.rand(3, 3)
  
      result = mls.block(
          [
              [SparseNDArray(r1), SparseNDArray(r2)],
              [SparseNDArray(r3), SparseNDArray(r4)],
          ]
      )
      expected = sps.bmat([[r1, r2], [r3, r4]])
      assert_array_equal(result, expected)
  
imports: import pickle
  import numpy
  import pytest
  import scipy.sparse
  from ...None import sparse
  from ..None import SparseNDArray, SparseVector, SparseMatrix
  from ..core import issparse
label_desc: Use image node_id 18 for calling a global function with example usage: test_sparse_block() without return types