code: def test_conjugate():
      a = Symbol("a", real=True)
      b = Symbol("b", real=True)
      c = Symbol("c", imaginary=True)
      d = Symbol("d", imaginary=True)
      x = Symbol("x")
      z = a + I * b + c + I * d
      zc = a - I * b - c + I * d
      assert conjugate(z) == zc
      assert conjugate(exp(z)) == exp(zc)
      assert conjugate(exp(I * x)) == exp(-I * conjugate(x))
      assert conjugate(z**5) == zc**5
      assert conjugate(abs(x)) == abs(x)
      assert conjugate(sign(z)) == sign(zc)
      assert conjugate(sin(z)) == sin(zc)
      assert conjugate(cos(z)) == cos(zc)
      assert conjugate(tan(z)) == tan(zc)
      assert conjugate(cot(z)) == cot(zc)
      assert conjugate(sinh(z)) == sinh(zc)
      assert conjugate(cosh(z)) == cosh(zc)
      assert conjugate(tanh(z)) == tanh(zc)
      assert conjugate(coth(z)) == coth(zc)
  
imports: from sympy.core.function import expand_complex
  from sympy.core.numbers import I, Integer, Rational, pi
  from sympy.core.power import Pow
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol, symbols
  from sympy.functions.elementary.complexes import Abs, conjugate, im, re, sign
  from sympy.functions.elementary.exponential import exp
  from sympy.functions.elementary.hyperbolic import cosh, coth, sinh, tanh
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import cos, cot, sin, tan
label_desc: Use image node_id 2 for calling a global function with example usage: test_conjugate() without return types