code: def test_ignored_attribute(self):
      import io
  
      G = nx.Graph()
      fh = io.BytesIO()
      G.add_node(1, int_attr=1)
      G.add_node(2, empty_attr="  ")
      G.add_edge(1, 2, int_attr=2)
      G.add_edge(2, 3, empty_attr="  ")
  
      import warnings
  
      with warnings.catch_warnings(record=True) as w:
          nx.write_pajek(G, fh)
          assert len(w) == 4
  
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 7 for calling the TestPajek obj's underlying member method code with example usage: obj.test_ignored_attribute() without return types