class ActiveModel::Serializer

def serializer_for(resource, options = {})
  if resource.respond_to?(:serializer_class)
    resource.serializer_class
  elsif resource.respond_to?(:to_ary)
    if Object.constants.include?(:ArraySerializer)
      ::ArraySerializer
    else
      ArraySerializer
    end
  else
    _const_get build_serializer_class(resource, options)
  end
end