code: def test_wright_functional(a, b, x):
      """Test functional relation of wright_bessel.
  
      Phi(a, b-1, z) = a*z*Phi(a, b+a, z) + (b-1)*Phi(a, b, z)
  
      Note that d/dx Phi(a, b, x) = Phi(a, b-1, x)
      See Eq. (22) of
      B. Stankovic, On the Function of E. M. Wright,
      Publ. de l' Institut Mathematique, Beograd,
      Nouvelle S`er. 10 (1970), 113-124.
      """
      assert_allclose(
          wright_bessel(a, b - 1, x),
          a * x * wright_bessel(a, b + a, x)
          + (b - 1) * wright_bessel(a, b, x),
          rtol=1e-8,
          atol=1e-8,
      )
  
file_path: scipy/scipy/special/tests/test_wright_bessel.py
imports: import pytest
  import numpy
  from numpy.testing import assert_equal, assert_allclose
  import scipy.special
  from scipy.special import rgamma, wright_bessel
label_desc: Use image node_id 3 for calling a global function with example usage: test_wright_functional(a, b, x) without return types