code: def test_inversion():
      from sympy.functions.special.bessel import besselj
      from sympy.functions.special.delta_functions import Heaviside
  
      def inv(f):
          return piecewise_fold(meijerint_inversion(f, s, t))
  
      assert inv(1 / (s**2 + 1)) == sin(t) * Heaviside(t)
      assert inv(s / (s**2 + 1)) == cos(t) * Heaviside(t)
      assert inv(exp(-s) / s) == Heaviside(t - 1)
      assert inv(1 / sqrt(1 + s**2)) == besselj(0, t) * Heaviside(t)
  
      # Test some antcedents checking.
      assert (
          meijerint_inversion(sqrt(s) / sqrt(1 + s**2), s, t) is None
      )
      assert inv(exp(s**2)) is None
      assert meijerint_inversion(exp(-(s**2)), s, t) is None
  
imports: from sympy.core.function import expand_func
  from sympy.core.numbers import I, Rational, oo, pi
  from sympy.core.singleton import S
  from sympy.core.sorting import default_sort_key
  from sympy.functions.elementary.complexes import Abs, arg, re, unpolarify
  from sympy.functions.elementary.exponential import exp, exp_polar, log
  from sympy.functions.elementary.hyperbolic import cosh, acosh
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.piecewise import Piecewise, piecewise_fold
  from sympy.functions.elementary.trigonometric import cos, sin, sinc, asin
  from sympy.functions.special.error_functions import erf, erfc
  from sympy.functions.special.gamma_functions import gamma, polygamma
  from sympy.functions.special.hyper import hyper, meijerg
  from sympy.integrals.integrals import Integral, integrate
  from sympy.simplify.hyperexpand import hyperexpand
  from sympy.simplify.simplify import simplify
  from sympy.integrals.meijerint import _rewrite_single, _rewrite1, meijerint_indefinite, _inflate_g, _create_lookup_table, meijerint_definite, meijerint_inversion
  from sympy.testing.pytest import slow
  from sympy.core.random import verify_numerically, random_complex_number
  from sympy.abc import x, y, a, b, c, d, s, t, z
label_desc: Use image node_id 9 for calling a global function with example usage: test_inversion() and returns: piecewise_fold