draw - Maxima 遇到 Lisp 错误：我不明白是什么问题

Question

我正在尝试在 wxmaxima 中做一个示例

  wxplot_size:[1024,768]$
wxanimate_framerate:2$
with_slider_draw(
   /* The parameter we want to assign to the slider and all values it can assume */
   R,Resistors,

   /* The thing we actually want to draw */
   key=concat("R=",float(R)," Ohm"),
   explicit(
    ev(Voltage(R,t)),
       t,0,20
   ),line_type=dots,color=black,
   key=concat("R=0.0 Ohm"),
   explicit(
       ev(Voltage(0,t)),
       t,0,20
   ),
   yrange=[-1,1],
   grid=true
)$

我收到以下错误。有谁能够帮我？

Maxima encountered a Lisp error:
 Condition in CDR [or a callee]: INTERNAL-SIMPLE-TYPE-ERROR: |$Resistors| is not of type LIST: 
Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.

对不起，但我不能把它作为代码谢谢