code: def vertex_adjacency_graph(mesh):
      
      g = nx.Graph()
      g.add_edges_from(mesh.edges_unique)
      return g
docs: Returns a networkx graph representing the vertices and
      their connections in the mesh.
  
      Parameters
      ----------
      mesh : Trimesh object
  
      Returns
      ---------
      graph : networkx.Graph
          Graph representing vertices and edges between
          them where vertices are nodes and edges are edges
  
      Examples
      ----------
      This is useful for getting nearby vertices for a given vertex,
      potentially for some simple smoothing techniques.
      >>> graph = mesh.vertex_adjacency_graph
      >>> graph.neighbors(0)
      > [1,3,4]