code: def test_to_meijerg():
      x = symbols("x")
      assert hyperexpand(expr_to_holonomic(sin(x)).to_meijerg()) == sin(
          x
      )
      assert hyperexpand(expr_to_holonomic(cos(x)).to_meijerg()) == cos(
          x
      )
      assert hyperexpand(expr_to_holonomic(exp(x)).to_meijerg()) == exp(
          x
      )
      assert hyperexpand(
          expr_to_holonomic(log(x)).to_meijerg()
      ).simplify() == log(x)
      assert (
          expr_to_holonomic(4 * x**2 / 3 + 7).to_meijerg()
          == 4 * x**2 / 3 + 7
      )
      assert hyperexpand(
          expr_to_holonomic(besselj(2, x), lenics=3).to_meijerg()
      ) == besselj(2, x)
      p = hyper((Rational(-1, 2), -3), (), x)
      assert from_hyper(p).to_meijerg() == hyperexpand(p)
      p = hyper((S.One, S(3)), (S(2),), x)
      assert (
          hyperexpand(from_hyper(p).to_meijerg()) - hyperexpand(p)
      ).expand() == 0
      p = from_hyper(hyper((-2, -3), (S.Half,), x))
      s = hyperexpand(hyper((-2, -3), (S.Half,), x))
      C_0 = Symbol("C_0")
      C_1 = Symbol("C_1")
      D_0 = Symbol("D_0")
      assert (
          hyperexpand(p.to_meijerg()).subs({C_0: 1, D_0: 0}) - s
      ).simplify() == 0
      p.y0 = {0: [1], S.Half: [0]}
      assert (hyperexpand(p.to_meijerg()) - s).simplify() == 0
      p = expr_to_holonomic(besselj(S.Half, x), initcond=False)
      assert (
          p.to_expr()
          - (D_0 * sin(x) + C_0 * cos(x) + C_1 * sin(x)) / sqrt(x)
      ).simplify() == 0
      p = expr_to_holonomic(
          besselj(S.Half, x),
          y0={
              Rational(-1, 2): [sqrt(2) / sqrt(pi), sqrt(2) / sqrt(pi)]
          },
      )
      assert (
          p.to_expr() - besselj(S.Half, x) - besselj(Rational(-1, 2), x)
      ).simplify() == 0
  
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 20 for calling a global function with example usage: test_to_meijerg() without return types