code: def analyze(self, structure, n=0):
          
          center = structure[n]
          neighbors = structure.get_sites_in_sphere(center.coords, self.cutoff)
          neighbors = [i[0] for i in sorted(neighbors, key=lambda s: s[1])]
          qvoronoi_input = np.array([s.coords for s in neighbors])
          voro = Voronoi(qvoronoi_input, qhull_options=self.qhull_options)
          vor_index = np.array([0, 0, 0, 0, 0, 0, 0, 0])
  
          for key in voro.ridge_dict:
              if 0 in key:  # This means if the center atom is in key
                  if -1 in key:  # This means if an infinity point is in key
                      raise ValueError("Cutoff too short.")
                  else:
                      try:
                          vor_index[len(voro.ridge_dict[key]) - 3] += 1
                      except IndexError:
                          # If a facet has more than 10 edges, it's skipped here.
                          pass
          return vor_index
docs: Performs Voronoi analysis and returns the polyhedra around atom n
          in Schlaefli notation.
  
          Args:
              structure (Structure): structure to analyze
              n (int): index of the center atom in structure
  
          Returns:
              voronoi index of n: <c3,c4,c6,c6,c7,c8,c9,c10>
                  where c_i denotes number of facets with i vertices.