code: public int getInt(String key) {
      	String value = get(key);
      	Utils.require(value != null, key + " parameter is not set");
      	try {
      		return Integer.parseInt(value);
          } catch (NumberFormatException e) {
              throw new IllegalArgumentException(key + " parameter should be a number");
          }
      }
docs: Returns an integer value by the key specified and throws exception if it was not specified