code: def test_DifferentialOperator():
      x = symbols("x")
      R, Dx = DifferentialOperators(QQ.old_poly_ring(x), "Dx")
      assert Dx == R.derivative_operator
      assert Dx == DifferentialOperator([R.base.zero, R.base.one], R)
      assert x * Dx + x**2 * Dx**2 == DifferentialOperator(
          [0, x, x**2], R
      )
      assert (x**2 + 1) + Dx + x * Dx**5 == DifferentialOperator(
          [x**2 + 1, 1, 0, 0, 0, x], R
      )
      assert (x * Dx + x**2 + 1 - Dx * (x**3 + x)) ** 3 == (
          -48 * x**6
      ) + (-57 * x**7) * Dx + (-15 * x**8) * Dx**2 + (
          -(x**9)
      ) * Dx**3
      p = (x * Dx**2 + (x**2 + 3) * Dx**5) * (Dx + x**2)
      q = (
          (2 * x)
          + (4 * x**2) * Dx
          + (x**3) * Dx**2
          + (20 * x**2 + x + 60) * Dx**3
          + (10 * x**3 + 30 * x) * Dx**4
          + (x**4 + 3 * x**2) * Dx**5
          + (x**2 + 3) * Dx**6
      )
      assert p == q
  
imports: from sympy.holonomic import DifferentialOperator, HolonomicFunction, DifferentialOperators, from_hyper, from_meijerg, expr_to_holonomic
  from sympy.holonomic.recurrence import RecurrenceOperators, HolonomicSequence
  from sympy.core import EulerGamma
  from sympy.core.numbers import I, Rational, pi
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol, symbols
  from sympy.functions.elementary.exponential import exp, log
  from sympy.functions.elementary.hyperbolic import asinh, cosh
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import cos, sin
  from sympy.functions.special.bessel import besselj
  from sympy.functions.special.beta_functions import beta
  from sympy.functions.special.error_functions import Ci, Si, erf, erfc
  from sympy.functions.special.gamma_functions import gamma
  from sympy.functions.special.hyper import hyper, meijerg
  from sympy.printing.str import sstr
  from sympy.series.order import O
  from sympy.simplify.hyperexpand import hyperexpand
  from sympy.polys.domains.integerring import ZZ
  from sympy.polys.domains.rationalfield import QQ
  from sympy.polys.domains.realfield import RR
label_desc: Use image node_id 1 for calling a global function with example usage: test_DifferentialOperator() without return types