code: def _widening_points(self, function_address):
          try:
              new_function = self.kb.functions[function_address]
          except KeyError:
              return [ ]
          if function_address not in self._function_widening_points:
              if not new_function.normalized:
                  new_function.normalize()
              widening_points = CFGUtils.find_widening_points(function_address, new_function.endpoints,
                                                                      new_function.graph)
              self._function_widening_points[function_address] = widening_points
          return self._function_widening_points[function_address]