code: def load_server_moduli(filename=None):
          
          Transport._modulus_pack = ModulusPack()
          # places to look for the openssh "moduli" file
          file_list = ["/etc/ssh/moduli", "/usr/local/etc/moduli"]
          if filename is not None:
              file_list.insert(0, filename)
          for fn in file_list:
              try:
                  Transport._modulus_pack.read_file(fn)
                  return True
              except IOError:
                  pass
          # none succeeded
          Transport._modulus_pack = None
          return False
docs: (optional)
          Load a file of prime moduli for use in doing group-exchange key
          negotiation in server mode.  It's a rather obscure option and can be
          safely ignored.
  
          In server mode, the remote client may request "group-exchange" key
          negotiation, which asks the server to send a random prime number that
          fits certain criteria.  These primes are pretty difficult to compute,
          so they can't be generated on demand.  But many systems contain a file
          of suitable primes (usually named something like ``/etc/ssh/moduli``).
          If you call `load_server_moduli` and it returns ``True``, then this
          file of primes has been loaded and we will support "group-exchange" in
          server mode.  Otherwise server mode will just claim that it doesn't
          support that method of key negotiation.
  
          :param str filename:
              optional path to the moduli file, if you happen to know that it's
              not in a standard location.
          :return:
              True if a moduli file was successfully loaded; False otherwise.
  
          .. note:: This has no effect when used in client mode.