code: public static Map<Transition, Collection<TileRef>> imports(Media config)
      {
          final Xml root = new Xml(config);
          final Collection<Xml> nodesTransition = root.getChildren(NODE_TRANSITION);
          final Map<Transition, Collection<TileRef>> transitions = new HashMap<>(nodesTransition.size());
  
          for (final Xml nodeTransition : nodesTransition)
          {
              final String groupIn = nodeTransition.readString(ATTRIBUTE_GROUP_IN);
              final String groupOut = nodeTransition.readString(ATTRIBUTE_GROUP_OUT);
              final String transitionType = nodeTransition.readString(ATTRIBUTE_TRANSITION_TYPE);
              final TransitionType type = TransitionType.from(transitionType);
              final Transition transition = new Transition(type, groupIn, groupOut);
  
              final Collection<Xml> nodesTileRef = nodeTransition.getChildren(TileConfig.NODE_TILE);
              final Collection<TileRef> tilesRef = importTiles(nodesTileRef);
  
              transitions.put(transition, tilesRef);
          }
  
          return transitions;
      }
docs: Import all transitions from configuration.
  
  @param config The transitions media (must not be <code>null</code>).
  @return The transitions imported with associated tiles.
  @throws LionEngineException If unable to read data.