code: public static void exports(Xml root, CollisionGroup group)
      {
          Check.notNull(root);
          Check.notNull(group);
  
          final Xml node = root.createChild(NODE_COLLISION);
          node.writeString(ATT_GROUP, group.getName());
  
          for (final CollisionFormula formula : group.getFormulas())
          {
              final Xml nodeFormula = node.createChild(CollisionFormulaConfig.NODE_FORMULA);
              nodeFormula.setText(formula.getName());
          }
      }
docs: Export the collision group data as a node.
  
  @param root The node root (must not be <code>null</code>).
  @param group The collision group to export (must not be <code>null</code>).
  @throws LionEngineException If error on writing.