I was building an operator with
ParameterTypeCheckBoxGroup, and I find when I want to get the parameters, it returned null
ParameterTypeCheckBoxGroup leads=new ParameterTypeCheckBoxGroup(PARAMETER_LEADS, "choose the leads to focus on");
for (String lead : leadName.getLead()){
leads.add(null,lead);
}step.focused_leads= stringToSelection(getParameterAsString(PARAMETER_LEADS));