code: def get_geometry_from_IUCr_symbol(self, IUCr_symbol):
          
          for gg in self.cg_list:
              if gg.IUCr_symbol == IUCr_symbol:
                  return gg
          raise LookupError(
              'No coordination geometry found with IUCr symbol "{symbol}"'.format(
                  symbol=IUCr_symbol))
docs: Returns the coordination geometry of the given IUCr symbol.
          :param IUCr_symbol: The IUCr symbol of the coordination geometry.