code: def test_visibility_graph__empty_series__empty_graph():
      null_graph = nx.visibility_graph(
          []
      )  # move along nothing to see here
      assert nx.is_empty(null_graph)
  
file_path: networkx/networkx/generators/tests/test_time_series.py
imports: import itertools
  import networkx
label_desc: Use image node_id 1 for calling a global function with example usage: test_visibility_graph__empty_series__empty_graph() without return types