code: def test_laplacian_centrality_unconnected_nodes():
      """laplacian_centrality on a unconnected node graph should return 0
  
      For graphs without edges, the Laplacian energy is 0 and is unchanged with
      node removal, so::
  
          LC(v) = LE(G) - LE(G - v) = 0 - 0 = 0
      """
      G = nx.empty_graph(3)
      assert nx.laplacian_centrality(G, normalized=False) == {
          0: 0,
          1: 0,
          2: 0,
      }
  
file_path: networkx/networkx/algorithms/centrality/tests/test_laplacian_centrality.py
imports: import pytest
  import networkx
label_desc: Use image node_id 3 for calling a global function with example usage: test_laplacian_centrality_unconnected_nodes() without return types