code: def setup_class(cls):
      cls.simple_data = """Creator "me"
  Version "xx"
  graph [
   comment "This is a sample graph"
   directed 1
   IsPlanar 1
   pos  [ x 0 y 1 ]
   node [
     id 1
     label "Node 1"
     pos [ x 1 y 1 ]
   ]
   node [
      id 2
      pos [ x 1 y 2 ]
      label "Node 2"
      ]
    node [
      id 3
      label "Node 3"
      pos [ x 1 y 3 ]
    ]
    edge [
      source 1
      target 2
      label "Edge from node 1 to node 2"
      color [line "blue" thickness 3]
  
    ]
    edge [
      source 2
      target 3
      label "Edge from node 2 to node 3"
    ]
    edge [
      source 3
      target 1
      label "Edge from node 3 to node 1"
    ]
  ]
  """
  
imports: import codecs
  import io
  import math
  from ast import literal_eval
  from contextlib import contextmanager
  from textwrap import dedent
  import pytest
  import networkx
  from networkx.readwrite.gml import literal_destringizer, literal_stringizer
label_desc: Use image node_id 1 for calling the TestGraph obj's underlying member method code with example usage: obj.setup_class(cls) without return types