code: def setup_class(cls):
      cls.data = """*network Tralala\n*vertices 4\n   1 "A1"         0.0938 0.0896   ellipse x_fact 1 y_fact 1\n   2 "Bb"         0.8188 0.2458   ellipse x_fact 1 y_fact 1\n   3 "C"          0.3688 0.7792   ellipse x_fact 1\n   4 "D2"         0.9583 0.8563   ellipse x_fact 1\n*arcs\n1 1 1  h2 0 w 3 c Blue s 3 a1 -130 k1 0.6 a2 -130 k2 0.6 ap 0.5 l "Bezier loop" lc BlueViolet fos 20 lr 58 lp 0.3 la 360\n2 1 1  h2 0 a1 120 k1 1.3 a2 -120 k2 0.3 ap 25 l "Bezier arc" lphi 270 la 180 lr 19 lp 0.5\n1 2 1  h2 0 a1 40 k1 2.8 a2 30 k2 0.8 ap 25 l "Bezier arc" lphi 90 la 0 lp 0.65\n4 2 -1  h2 0 w 1 k1 -2 k2 250 ap 25 l "Circular arc" c Red lc OrangeRed\n3 4 1  p Dashed h2 0 w 2 c OliveGreen ap 25 l "Straight arc" lc PineGreen\n1 3 1  p Dashed h2 0 w 5 k1 -1 k2 -20 ap 25 l "Oval arc" c Brown lc Black\n3 3 -1  h1 6 w 1 h2 12 k1 -2 k2 -15 ap 0.5 l "Circular loop" c Red lc OrangeRed lphi 270 la 180"""
      cls.G = nx.MultiDiGraph()
      cls.G.add_nodes_from(["A1", "Bb", "C", "D2"])
      cls.G.add_edges_from(
          [
              ("A1", "A1"),
              ("A1", "Bb"),
              ("A1", "C"),
              ("Bb", "A1"),
              ("C", "C"),
              ("C", "D2"),
              ("D2", "Bb"),
          ]
      )
  
      cls.G.graph["name"] = "Tralala"
  
file_path: networkx/networkx/readwrite/tests/test_pajek.py
imports: import networkx
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 1 for calling the TestPajek obj's underlying member method code with example usage: obj.setup_class(cls) without return types