code: @SuppressWarnings("unchecked")
    public <T> List<T> get(PropertyListKey<T> property) {
      if (contains(property)) {
        return (List<T>) properties.get(property.getName());
      } else {
        return new ArrayList<T>();
      }
    }
docs: Returns the list to which the specified property key is mapped, or
  an empty list if this properties contains no mapping for the property key.
  Note that the empty list is not mapped to the property key.
  
  @param property
  the property key whose associated list is to be returned
  @return the list to which the specified property key is mapped, or
  an empty list if this properties contains no mapping for the property key
  
  @see #addListItem(PropertyListKey, Object)