code: function getTypesFromHandlers(handlers) {
    var types = keys(handlers);
    types = types.map(k => k.replace(/_.*/, ''));
    if (types.indexOf('end') !== -1) {
      types.push('add', 'update', 'delete');
    }
    return types;
  }
docs: Prepare the list of `type`s to pass to O.o, based on handler methods. Even if only `end` is present, we need to add `add` etc. If handler named `type_name` is there, register `type` as handled.