[error] remove characters from elements in a multi select field

Hi,

I have stringlist variable (multi select field) containing different elements, such as type1, type2.
I had to import excel data in this field and because of input variations I now end up having similar elements but with or without special characters around them: type1,[type1],(type1), type2, (type2), etc.

I would like to remove the brackets in the example above (so as to end up with harmonised elements) but I am not sure how to do that. I managed to get the following:

for each tobeupdated in Ricci_Droit_Form [Statut_FR == "Publiable"]
{
olist=tobeupdated.BRANCH;
ghostlist=olist;
for each element in olist
    {
        if(element.contains(")"))
        {
            elementx=element.toString();
            updatedelement=elementx.remove("(");
            updatedelement2=updatedelement.remove(")");
            olist.removeElement(element);
            updatedelement3=updatedelement2+".";
            olist.Add(updatedelement3);
        }
        else
        {
        }
    }
tobeupdated.BRANCH=olist;
}

However, when I run this script from a stateless form, the following error appears:

Error details:
Error occured while executing on click script.
Unable to update data on the form variable
Error occured.

Could anyone help?

Best