code: def get_cart_coords(self):
          
          def to_s(x):
              return "%0.6f" % x
  
          outs = []
          for i, site in enumerate(self._mol):
              outs.append(" ".join([site.species_string,
                                    " ".join([to_s(j) for j in site.coords])]))
          return "\n".join(outs)
docs: Return the cartesian coordinates of the molecule