code: def test_bool(self):
      s = """<?xml version="1.0" encoding="UTF-8"?>
  <graphml xmlns="http://graphml.graphdrawing.org/xmlns"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns
           http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
    <key id="d0" for="node" attr.name="test" attr.type="boolean">
      <default>false</default>
    </key>
    <graph id="G" edgedefault="directed">
      <node id="n0">
        <data key="d0">true</data>
      </node>
      <node id="n1"/>
      <node id="n2">
        <data key="d0">false</data>
      </node>
      <node id="n3">
        <data key="d0">FaLsE</data>
      </node>
      <node id="n4">
        <data key="d0">True</data>
      </node>
      <node id="n5">
        <data key="d0">0</data>
      </node>
      <node id="n6">
        <data key="d0">1</data>
      </node>
    </graph>
  </graphml>
  """
      fh = io.BytesIO(s.encode("UTF-8"))
      G = nx.read_graphml(fh)
      H = nx.parse_graphml(s)
      for graph in [G, H]:
          assert graph.nodes["n0"]["test"]
          assert not graph.nodes["n2"]["test"]
          assert not graph.nodes["n3"]["test"]
          assert graph.nodes["n4"]["test"]
          assert not graph.nodes["n5"]["test"]
          assert graph.nodes["n6"]["test"]
  
imports: import io
  import pytest
  import networkx
  from networkx.readwrite.graphml import GraphMLWriter
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 15 for calling the TestReadGraphML obj's underlying member method code with example usage: obj.test_bool() without return types