code: protected Map<Instance, Boolean> checkAccessToInstances(final List<Instance> _instances)
          throws EFapsException
      {
          final Map<Type, List<Instance>> types = new HashMap<>();
          for (final Instance instance : _instances) {
              final List<Instance> list;
              if (!types.containsKey(instance.getType())) {
                  list = new ArrayList<>();
                  types.put(instance.getType(), list);
              } else {
                  list = types.get(instance.getType());
              }
              list.add(instance);
          }
          // check the access for the given instances
          for (final Entry<Type, List<Instance>> entry : types.entrySet()) {
              this.accessMap.putAll(entry.getKey().checkAccess(entry.getValue(), AccessTypeEnums.SHOW.getAccessType()));
          }
          return this.accessMap;
      }
docs: Used to check the access to e.g. TreeMenus.
  
  @param _instances Instances that must be checked for access
  @return Map with Instance to Boolean
  @throws EFapsException on error