code: def simulationarchive_snapshot(self, filename):
          
          clibrebound.reb_simulationarchive_snapshot(byref(self), c_char_p(filename.encode("ascii")))
docs: Take a snapshot and save it to a SimulationArchive file.
          If the file does not exist yet, a new one will be created. 
          If the file does exist, a snapshot will be appended.
          
          Arguments
          ---------
          filename : str
              Filename of the binary file.