Need help in framing a condition on a gateway sequence that gets the count of values selected in a multiselect field in a form

I am trying to frame a condition on a gateway which decides the sequence based on the number of values selected in a multiselect field in a form. Can somebody help me with the condition?
I tried using below condition, but get XML parsing error:
${count(execution.getVariable(‘bfachplanner’)) > 1}, where bfachplanner is the code of the property on the form.