code: def register(host=DFLT_ADDRESS[0], port=DFLT_ADDRESS[1],
               signum=signal.SIGUSR1):
      
      _pdbhandler._register(host, port, signum)
docs: Register a pdb handler for signal 'signum'.
  
      The handler sets pdb to listen on the ('host', 'port') internet address
      and to start a remote debugging session on accepting a socket connection.