code: def add_letter_to_axis(ax, let, col, x, y, height):
      
      if len(let) == 2:
          colors = [col, "white"]
      elif len(let) == 1:
          colors = [col]
      else:
          raise ValueError("3 or more Polygons are not supported")
  
      for polygon, color in zip(let, colors):
          new_polygon = affinity.scale(
              polygon, yfact=height, origin=(0, 0, 0))
          new_polygon = affinity.translate(
              new_polygon, xoff=x, yoff=y)
          patch = PolygonPatch(
              new_polygon, edgecolor=color, facecolor=color)
          ax.add_patch(patch)
      return
docs: Add 'let' with position x,y and height height to matplotlib axis 'ax'.