code: def test_as_linearoperator(A):
      L = spla.aslinearoperator(A)
      npt.assert_allclose(L * [1, 2, 3, 4], A @ [1, 2, 3, 4])
  
imports: import pytest
  import numpy
  import numpy.testing
  import scipy.sparse
  import scipy.sparse.linalg
  from scipy._lib._util import VisibleDeprecationWarning
label_desc: Use image node_id 18 for calling a global function with example usage: test_as_linearoperator(A) without return types