class ActiveStorage::Service::Registry

def fetch(name)
  services.fetch(name.to_sym) do |key|
    if configurations.include?(key)
      services[key] = configurator.build(key)
    else
      if block_given?
        yield key
      else
        raise KeyError, "Missing configuration for the #{key} Active Storage service. " \
          "Configurations available for the #{configurations.keys.to_sentence} services."
      end
    end
  end
end