docs: def _set_cluster(self):
          """
          Compute and set the cluster of atoms as a Molecule object. The siteato
          coordinates are translated such that the absorbing atom(aka central
          atom) is at the origin.
  
          Returns:
              Molecule
          """
          center = self.struct[self.center_index].coords
          sphere = self.struct.get_neighbors(self.struct[self.center_index], self.radius)
  
          symbols = [self.absorbing_atom]
          coords = [[0, 0, 0]]
          for i, site_dist in enumerate(sphere):
              site_symbol = re.sub(r"[^aA-zZ]+", "", site_dist[0].species_string)
              symbols.append(site_symbol)
              coords.append(site_dist[0].coords - center)
          return Molecule(symbols, coords)