module ViewModel::ActiveRecord::CollectionNestedController

def append(serialize_context: new_serialize_context, deserialize_context: new_deserialize_context, lock_owner: nil)
  assoc_view = nil
  pre_rendered = owner_viewmodel.transaction do
    update_hash, refs = parse_viewmodel_updates
    before = parse_relative_position(:before)
    after  = parse_relative_position(:after)
    if before && after
      raise ViewModel::DeserializationError::InvalidSyntax.new('Can not provide both `before` and `after` anchors for a collection append')
    end
    owner_view = owner_viewmodel.find(owner_viewmodel_id, eager_include: false, lock: lock_owner)
    assoc_view = owner_view.append_associated(association_name,
                                              update_hash,
                                              references: refs,
                                              before: before,
                                              after: after,
                                              deserialize_context: deserialize_context)
    ViewModel::Callbacks.wrap_serialize(owner_view, context: serialize_context) do
      child_context = owner_view.context_for_child(association_name, context: serialize_context)
      ViewModel.preload_for_serialization(assoc_view)
      assoc_view = yield(assoc_view) if block_given?
      prerender_viewmodel(assoc_view, serialize_context: child_context)
    end
  end
  render_json_string(pre_rendered)
  assoc_view
end