code: def test_DDM_eye():
      ddmz = DDM.eye(3, QQ)
      f = lambda i, j: QQ(1) if i == j else QQ(0)
      assert list(ddmz) == [
          [f(i, j) for i in range(3)] for j in range(3)
      ]
      assert ddmz.shape == (3, 3)
      assert ddmz.domain == QQ
  
imports: from sympy.testing.pytest import raises
  from sympy.external.gmpy import GROUND_TYPES
  from sympy.polys import ZZ, QQ
  from sympy.polys.matrices.ddm import DDM
  from sympy.polys.matrices.exceptions import DMShapeError, DMNonInvertibleMatrixError, DMDomainError, DMBadInputError
label_desc: Use image node_id 8 for calling a global function with example usage: test_DDM_eye() without return types