code: def test_polymatrix_getitem():
      M = PolyMatrix([[1, 2], [3, 4]], x)
      assert M[:, :] == M
      assert M[0, :] == PolyMatrix([[1, 2]], x)
      assert M[:, 0] == PolyMatrix([1, 3], x)
      assert M[0, 0] == Poly(1, x, domain=QQ)
      assert M[0] == Poly(1, x, domain=QQ)
      assert M[:2] == [Poly(1, x, domain=QQ), Poly(2, x, domain=QQ)]
  
file_path: sympy/sympy/polys/tests/test_polymatrix.py
imports: from sympy.testing.pytest import raises
  from sympy.polys.polymatrix import PolyMatrix
  from sympy.polys import Poly
  from sympy.core.singleton import S
  from sympy.matrices.dense import Matrix
  from sympy.polys.domains.integerring import ZZ
  from sympy.polys.domains.rationalfield import QQ
  from sympy.abc import x, y
label_desc: Use image node_id 6 for calling a global function with example usage: test_polymatrix_getitem() without return types