code: public String keyValueList() {
  		String separator = "";
  		StringBuilder buffer = new StringBuilder();
  
  		for (int i = 0; i < names.size(); i++) {
  			buffer.append(separator + "?");
  			separator = ", ";
  		}
  
  		return buffer.toString();
  	}
docs: Key value list.
  
  @return the string