class ViewModel::ActiveRecord::UpdateContext

def new_update(viewmodel, update_data, reparent_to: nil, reposition_to: nil)
  update = ViewModel::ActiveRecord::UpdateOperation.new(
    viewmodel, update_data, reparent_to: reparent_to, reposition_to: reposition_to)
  if (vm_ref = update.viewmodel_reference).present?
    check_unique_update!(vm_ref)
  end
  update
end