code: def test_issue_19113():
      eq = y**3 - y + 1
      # generator is a canonical x in RootOf
      assert str(Poly(eq).real_roots()) == "[CRootOf(x**3 - x + 1, 0)]"
      assert (
          str(Poly(eq.subs(y, tan(y))).real_roots())
          == "[CRootOf(x**3 - x + 1, 0)]"
      )
      assert (
          str(Poly(eq.subs(y, tan(x))).real_roots())
          == "[CRootOf(x**3 - x + 1, 0)]"
      )
  
imports: from sympy.polys.polytools import Poly
  import sympy.polys.rootoftools
  from sympy.polys.rootoftools import rootof, RootOf, CRootOf, RootSum, _pure_key_dict
  from sympy.polys.polyerrors import MultivariatePolynomialError, GeneratorsNeeded, PolynomialError
  from sympy.core.function import Function, Lambda
  from sympy.core.numbers import Float, I, Rational
  from sympy.core.relational import Eq
  from sympy.core.singleton import S
  from sympy.functions.elementary.exponential import exp, log
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import tan
  from sympy.integrals.integrals import Integral
  from sympy.polys.orthopolys import legendre_poly
  from sympy.solvers.solvers import solve
  from sympy.testing.pytest import raises, slow
  from sympy.core.expr import unchanged
  from sympy.abc import a, b, x, y, z, r
label_desc: Use image node_id 33 for calling a global function with example usage: test_issue_19113() without return types