code: def test_empty_digraph(self):
      with pytest.raises(nx.NetworkXNotImplemented):
          bytesIO = io.BytesIO()
          bipartite.write_edgelist(nx.DiGraph(), bytesIO)
  
imports: import io
  import pytest
  import networkx
  from networkx.algorithms import bipartite
  from networkx.utils import edges_equal, graphs_equal, nodes_equal
label_desc: Use image node_id 14 for calling the TestEdgelist obj's underlying member method code with example usage: obj.test_empty_digraph() without return types