Redirect a system stream to a specified file.
            `system_stream` is a standard system stream such as
            ``sys.stdout``. `target_stream` is an open file object that
            should replace the corresponding system stream object.
            If `target_stream` is ``None``, defaults to opening the
            operating system's null device and using its file descriptor.

def redirect_stream(system_stream, target_stream):
        """ Redirect a system stream to a specified file.
            `system_stream` is a standard system stream such as
            ``sys.stdout``. `target_stream` is an open file object that
            should replace the corresponding system stream object.
            If `target_stream` is ``None``, defaults to opening the
            operating system's null device and using its file descriptor.
            """
        if target_stream is None:
            target_fd = os.open(os.devnull, os.O_RDWR)
        else:
            target_fd = target_stream.fileno()
        os.dup2(target_fd, system_stream.fileno())