code: def test_DynkinDiagram():
      c = DynkinDiagram("A3")
      diag = "0---0---0\n1   2   3"
      assert c == diag
      ct = DynkinDiagram(["B", 3])
      diag2 = "0---0=>=0\n1   2   3"
      assert ct == diag2
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_DynkinDiagram() without return types