code: public String convertListToString(Object listOrString) {
  
  		if (listOrString == null) {
  			return null;
  		}
  
  		if (listOrString instanceof Collection) {
  			List<String> list = (List<String>) listOrString;
  
  			return StringUtils.join(list, ",");
  
  		}
  
  		return listOrString.toString();
  
  	}
docs: Handles the fact that bh rest api sends Strings as json arrays if they
  are setup as multipickers in the fieldmaps.
  
  @param listOrString
  @return