code: def calculate_megno(self):
          
          if self._calculate_megno==0:
              raise RuntimeError("MEGNO cannot be calculated. Make sure to call init_megno() after adding all particles but before integrating the simulation.")
  
          clibrebound.reb_tools_calculate_megno.restype = c_double
          return clibrebound.reb_tools_calculate_megno(byref(self))
docs: Return the current MEGNO value.
          Note that you need to call init_megno() before the start of the simulation.