invalid default drawing: #f

[Pytheas01]

Hello, thefollowing code generates an « invalid default drawing » error in LispPad 2.1 on IPadOs 18.2:

import (lispkit draw chart bar))

(draw-bar-chart 
  (list (bar "Jan" 0) (bar "Feb" 2) (bar "Mar" 6) (bar "Apr" 9) (bar "May" 14) (bar "Jun" 16) (bar "Jul" 19) (bar "Aug" 18) (bar "Sep" 15) (bar "Oct" 11) (bar "Nov" 5) (bar "Dec" 2)) 
  gray 5 "Temperature [C°]" "Month" 
  (point 50 105) (make-bar-chart-config 'size: (size 495 200))
  (make-legend-config 'font: (font "Helvetica" 7) 'stroke-width: 0.4 'entry-pad: 5 'sample-area-width: 16 'sample-length: 8 'horizontal-offset: 50))