code: def test_default_is_matrix_stacks(fn):
      """Same idea as `test_default_construction_fn_matrices`, but for the
      stacking creation functions."""
      A = scipy.sparse.coo_matrix(np.eye(2))
      B = scipy.sparse.coo_matrix([[0, 1], [1, 0]])
      m = fn([A, B])
      assert not isinstance(m, scipy.sparse.sparray)
  
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 44 for calling a global function with example usage: test_default_is_matrix_stacks(fn) without return types