class ActiveModel::Serializer

def self.serializer_for(resource_or_class, options = {})
  if resource_or_class.respond_to?(:serializer_class)
    resource_or_class.serializer_class
  elsif resource_or_class.respond_to?(:to_ary)
    config.collection_serializer
  else
    resource_class = resource_or_class.class == Class ? resource_or_class : resource_or_class.class
    options.fetch(:serializer) { get_serializer_for(resource_class, options[:namespace]) }
  end
end