code: def test_SDM_nullspace():
      # More tests are in test_nullspace.py
      A = SDM({0: {0: QQ(1), 1: QQ(1)}}, (2, 2), QQ)
      assert A.nullspace()[0] == SDM(
          {0: {0: QQ(-1), 1: QQ(1)}}, (1, 2), QQ
      )
  
imports: from itertools import product
  from sympy.core.singleton import S
  from sympy.external.gmpy import GROUND_TYPES
  from sympy.testing.pytest import raises
  from sympy.polys.domains import QQ, ZZ, EXRAW
  from sympy.polys.matrices.sdm import SDM
  from sympy.polys.matrices.ddm import DDM
  from sympy.polys.matrices.exceptions import DMBadInputError, DMDomainError, DMShapeError
label_desc: Use image node_id 37 for calling a global function with example usage: test_SDM_nullspace() without return types