[Closed] Custom attribute problem

Hi Folks,

I am doing an autorig in 3dsmax for my rigging tools, and after 2 years without touching anything in Maxscript, I decided to improve the tool, but I have a problem when adding a custom attribute.
The point is before the script was runing just fine, indeed it works fine, but when i isolate the function which add custom attribute, the function doesn’t work anymore…
here is the script:

 
   fn addCA theNode   =
   (   
      
      NewAttr = EmptyModifier()
      NewAttr.name="IK_Blend"
      addmodifier theNode NewAttr
      IKFK_CA = attributes ik_switch
      (
         parameters  PRM_IKFK_CA  rollout:IKSwitch
               
         (
            swtch_Ik_fk type:#float ui: (sp_IKFK)  default: 1
            stretchP type:#float ui: (stretchSp,stretchSl)  default: 1
            softP type:#float ui: (softSp,softSl)  default: 0
            pinP type:#float ui: (pinSp,pinSl)  default: 0
            fkBtn type:#boolean ui: (ui_FKIK)  default: false
            ikBtn type:#boolean ui: (ui_IKFK)  default: false
            freeOt type:#boolean ui: (freeOrient) default: false
            freeElbo type:#boolean ui: (freeElbow) default: false
         )
               
         rollout IKSwitch "FK <---> IK"
         (
            button ui_FKIK "FK" width:30 height:30 align:#Left across: 3
            spinner sp_IKFK "Blend" range:[0,1,1] fieldWidth: 40 align:#center across:1
            button ui_IKFK "IK" width:30 height:30 align:#Right 
            spinner stretchSp "" range:[0,1,0]
            slider stretchSl "Auto Stretch" range:[0,1,0] offset:[0,-20]
            spinner softSp "" range:[0,10,0]
            slider softSl "Soft IK" range:[0,10,0] offset:[0,-20]
            spinner  pinSp "" range:[0,1,0]
            slider pinSl "Pin Elbow" range:[0,1,0] offset:[0,-20]
            checkbutton freeOrient "Arm Free Orient" checked: false width:80 height:30 align:#center
            checkbutton freeElbow "Free Elbow" checked: false width:80 height:30 align:#center
                  
         )
               
         rollout CopyArms "Paste Pose to R side"
         (
            button CopyPaste "Paste Arms Pose" width:180 height:30 
            button CopyPasteHands "Paste Hand Pose" width:180 height:30 
         )
               
      )
      custattributes.add  theNode.modifiers["IK_Blend"] IKFK_CA baseobject: False 
   )

the max error returned is:

 
-- Error occurred in anonymous codeblock; filename: H:\Personel\Autorig\Fonction addCA.ms; position: 1704; line: 51
-- Unknown property: "modifiers" in $selection
-- MAXScript callstack:
--   thread data: threadID:17928
--   ------------------------------------------------------
--   [stack level: 0]
--   In addCA(); filename: H:\Personel\Autorig\Fonction addCA.ms; position: 1705; line: 51
--      Parameters:
--         theNode: $selection
--      Locals:
--         theNode: $selection
--         IKFK_CA: <AttributeDef:ik_switch>
--      Externals:
--         owner: undefined
--   ------------------------------------------------------
--   [stack level: 1]
--   called from top-level

I am on max 2017.

Thanks