code: def test_lsmr(matrices):
      A_dense, A_sparse, b = matrices
      res0 = splin.lsmr(A_dense, b)
      res = splin.lsmr(A_sparse, b)
      assert_allclose(res[0], res0[0], atol=1.8e-5)
  
imports: import pytest
  import numpy
  import scipy.sparse
  import scipy.sparse.linalg
  from numpy.testing import assert_allclose
label_desc: Use image node_id 6 for calling a global function with example usage: test_lsmr(matrices) without return types