parameters: (system_stream, target_stream)
docstring: 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.
docstring_summary: Redirect a system stream to a specified file.
docstring_tokens: Redirect a system stream to a specified file .
function: 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())
function_tokens: def redirect_stream ( system_stream , target_stream ) : 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 ( ) )