code: def clear(self, fg, attr, bg):
          
          line = [(ord(u" "), fg, attr, bg, 1) for _ in range(self._width)]
          self._double_buffer = [line[:] for _ in range(self._height)]
docs: Clear the double-buffer.
  
          This does not clear the screen buffer and so the next call to deltas will still show all changes.
  
          :param fg: The foreground colour to use for the new buffer.
          :param attr: The attribute value to use for the new buffer.
          :param bg: The background colour to use for the new buffer.