code: def test_vfield():
      ns = {"vfield": vfield, "QQ": QQ}
      exec('F = vfield("f", QQ)', ns)
      exec("assert f == F.gens[0]", ns)
  
      exec('F = vfield("fb fbb fcc fzz _fx", QQ)', ns)
      exec("assert fb == F.gens[0]", ns)
      exec("assert fbb == F.gens[1]", ns)
      exec("assert fcc == F.gens[2]", ns)
      exec("assert fzz == F.gens[3]", ns)
      exec("assert _fx == F.gens[4]", ns)
  
      exec('F = vfield(["fd", "fe", "ffg"], QQ)', ns)
      exec("assert fd == F.gens[0]", ns)
      exec("assert fe == F.gens[1]", ns)
      exec("assert ffg == F.gens[2]", ns)
  
imports: from sympy.polys.rings import vring
  from sympy.polys.fields import vfield
  from sympy.polys.domains import QQ
label_desc: Use image node_id 2 for calling a global function with example usage: test_vfield() without return types