def _write(self, dest_fd):
    buffer = self.buffers[dest_fd]
    if buffer:
        self.buffers[dest_fd] = buffer[os.write(dest_fd, buffer):]
def _write(self, dest_fd):
    buffer = self.buffers[dest_fd]
    if buffer:
        self.buffers[dest_fd] = buffer[os.write(dest_fd, buffer):]