How to use the billiard.reduction function in billiard

(_winapi.FILE_GENERIC_WRITE if conn.writable else 0))
        dh = reduction.DupHandle(conn.fileno(), access)
        return rebuild_pipe_connection, (dh, conn.readable, conn.writable)

    def rebuild_pipe_connection(dh, readable, writable):
        return PipeConnection(detach(dh), readable, writable)
    reduction.register(PipeConnection, reduce_pipe_connection)

else:
    def reduce_connection(conn):
        df = reduction.DupFd(conn.fileno())
        return rebuild_connection, (df, conn.readable, conn.writable)

    def rebuild_connection(df, readable, writable):
        return Connection(detach(df), readable, writable)
    reduction.register(Connection, reduce_connection)

def _launch(self, process_obj):
        prep_data = spawn.get_preparation_data(process_obj._name)
        buf = io.BytesIO()
        context.set_spawning_popen(self)
        try:
            reduction.dump(prep_data, buf)
            reduction.dump(process_obj, buf)
        finally:
            context.set_spawning_popen(None)

        self.sentinel, w = forkserver.connect_to_new_process(self._fds)
        with io.open(w, 'wb', closefd=True) as f:
            f.write(buf.getbuffer())
        self.pid = forkserver.read_unsigned(self.sentinel)

def _serve_one(s, listener, alive_r, handler):
    # close unnecessary stuff and reset SIGCHLD handler
    listener.close()
    os.close(alive_r)
    signal.signal(signal.SIGCHLD, handler)

    # receive fds from parent process
    fds = reduction.recvfds(s, MAXFDS_TO_SEND + 1)
    s.close()
    assert len(fds) <= MAXFDS_TO_SEND

    (child_r, child_w, _forkserver._forkserver_alive_fd,
     stfd, _forkserver._inherited_fds) = __unpack_fds(*fds)
    semaphore_tracker._semaphore_tracker._fd = stfd

    # send pid to client processes
    write_unsigned(child_w, os.getpid())

    # reseed random number generator
    if 'random' in sys.modules:
        import random
        random.seed()

    # run process object received over pipe

global xmlrpclib
        import xmlrpclib  # noqa
        obj = Listener.accept(self)
        return ConnectionWrapper(obj, _xml_dumps, _xml_loads)


def XmlClient(*args, **kwds):
    global xmlrpclib
    import xmlrpclib  # noqa
    return ConnectionWrapper(Client(*args, **kwds), _xml_dumps, _xml_loads)


if sys.platform == 'win32':
    ForkingPickler.register(socket.socket, reduction.reduce_socket)
    ForkingPickler.register(Connection, reduction.reduce_connection)
    ForkingPickler.register(PipeConnection, reduction.reduce_pipe_connection)
else:
    ForkingPickler.register(socket.socket, reduction.reduce_socket)
    ForkingPickler.register(Connection, reduction.reduce_connection)

obj = Listener.accept(self)
        return ConnectionWrapper(obj, _xml_dumps, _xml_loads)


def XmlClient(*args, **kwds):
    global xmlrpclib
    import xmlrpclib  # noqa
    return ConnectionWrapper(Client(*args, **kwds), _xml_dumps, _xml_loads)


if sys.platform == 'win32':
    ForkingPickler.register(socket.socket, reduction.reduce_socket)
    ForkingPickler.register(Connection, reduction.reduce_connection)
    ForkingPickler.register(PipeConnection, reduction.reduce_pipe_connection)
else:
    ForkingPickler.register(socket.socket, reduction.reduce_socket)
    ForkingPickler.register(Connection, reduction.reduce_connection)

def detach(self):
            '''Get the fd.  This should only be called once.'''
            with _resource_sharer.get_connection(self._id) as conn:
                return reduction.recv_handle(conn)

return rebuild_connection, (ds, conn.readable, conn.writable)

    def rebuild_connection(ds, readable, writable):
        sock = ds.detach()
        return Connection(detach(sock), readable, writable)
    reduction.register(Connection, reduce_connection)

    def reduce_pipe_connection(conn):
        access = ((_winapi.FILE_GENERIC_READ if conn.readable else 0) |
                  (_winapi.FILE_GENERIC_WRITE if conn.writable else 0))
        dh = reduction.DupHandle(conn.fileno(), access)
        return rebuild_pipe_connection, (dh, conn.readable, conn.writable)

    def rebuild_pipe_connection(dh, readable, writable):
        return PipeConnection(detach(dh), readable, writable)
    reduction.register(PipeConnection, reduce_pipe_connection)

else:
    def reduce_connection(conn):
        df = reduction.DupFd(conn.fileno())
        return rebuild_connection, (df, conn.readable, conn.writable)

    def rebuild_connection(df, readable, writable):
        return Connection(detach(df), readable, writable)
    reduction.register(Connection, reduce_connection)

None, None, False, 0, None, None, None)
                close_thread_handle(ht)
            except:
                _winapi.CloseHandle(rhandle)
                raise

            # set attributes of self
            self.pid = pid
            self.returncode = None
            self._handle = hp
            self.sentinel = int(hp)

            # send information to child
            context.set_spawning_popen(self)
            try:
                reduction.dump(prep_data, to_child)
                reduction.dump(process_obj, to_child)
            finally:
                context.set_spawning_popen(None)

)
                    util.Finalize(self, os.close, (self.fd,))
                    os.unlink(name)
                    os.ftruncate(self.fd, size)
            self.buffer = mmap.mmap(self.fd, self.size)

    def reduce_arena(a):
        if a.fd == -1:
            raise ValueError('Arena is unpicklable because'
                             'forking was enabled when it was created')
        return rebuild_arena, (a.size, reduction.DupFd(a.fd))

    def rebuild_arena(size, dupfd):
        return Arena(size, dupfd.detach())

    reduction.register(Arena, reduce_arena)

#
# Class allowing allocation of chunks of memory from arenas
#


class Heap(object):

    _alignment = 8

    def __init__(self, size=mmap.PAGESIZE):
        self._lastpid = os.getpid()
        self._lock = threading.Lock()
        self._size = size
        self._lengths = []
        self._len_to_seq = {}

def duplicate_for_child(self, handle):
        assert self is context.get_spawning_popen()
        return reduction.duplicate(handle, self.sentinel)