code: def show_message(
              self,
              text_string,
              scroll_speed=.1,
              text_colour=[255, 255, 255],
              back_colour=[0, 0, 0]
          ):
          
  
          # We must rotate the pixel map left through 90 degrees when drawing
          # text, see _load_text_assets
          previous_rotation = self._rotation
          self._rotation -= 90
          if self._rotation < 0:
              self._rotation = 270
          dummy_colour = [None, None, None]
          string_padding = [dummy_colour] * 64
          letter_padding = [dummy_colour] * 8
          # Build pixels from dictionary
          scroll_pixels = []
          scroll_pixels.extend(string_padding)
          for s in text_string:
              scroll_pixels.extend(self._trim_whitespace(self._get_char_pixels(s)))
              scroll_pixels.extend(letter_padding)
          scroll_pixels.extend(string_padding)
          # Recolour pixels as necessary
          coloured_pixels = [
              text_colour if pixel == [255, 255, 255] else back_colour
              for pixel in scroll_pixels
          ]
          # Shift right by 8 pixels per frame to scroll
          scroll_length = len(coloured_pixels) // 8
          for i in range(scroll_length - 8):
              start = i * 8
              end = start + 64
              self.set_pixels(coloured_pixels[start:end])
              time.sleep(scroll_speed)
          self._rotation = previous_rotation
docs: Scrolls a string of text across the LED matrix using the specified
          speed and colours