code: public static CollisionGroupConfig imports(Xml root, MapTileCollision map)
      {
          Check.notNull(root);
          Check.notNull(map);
  
          final Collection<Xml> childrenCollision = root.getChildren(NODE_COLLISION);
          final Map<String, CollisionGroup> groups = new HashMap<>(childrenCollision.size());
  
          for (final Xml node : childrenCollision)
          {
              final Collection<Xml> childrenFormula = node.getChildren(CollisionFormulaConfig.NODE_FORMULA);
              final Collection<CollisionFormula> formulas = new ArrayList<>(childrenFormula.size());
  
              for (final Xml formula : childrenFormula)
              {
                  final String formulaName = formula.getText();
                  formulas.add(map.getCollisionFormula(formulaName));
              }
  
              final String groupName = node.readString(ATT_GROUP);
              final CollisionGroup collision = new CollisionGroup(groupName, formulas);
              groups.put(groupName, collision);
          }
  
          return new CollisionGroupConfig(groups);
      }
docs: Create the collision group data from node.
  
  @param root The node root reference (must not be <code>null</code>).
  @param map The map reference (must not be <code>null</code>).
  @return The collisions group data.
  @throws LionEngineException If unable to read node.