# Retrieve an `Object` stored via `[]=` function
	#
	# Returns `null` if there's no serialized object corresponding to the given key
	# Make sure that the serialized object is `serialize` or that it redefines
	# the appropriate methods. Refer to `Serializable` documentation for further details
	fun [](key: String): nullable Object
	do
		var serialized_string = self.string(key, "")

		if serialized_string == "" then return null

		var deserializer = new JsonDeserializer(serialized_string)
		var deserialized = deserializer.deserialize

		var errors = deserializer.errors
		if errors.not_empty then
			# An update may have broken the versioning compatibility
			print_error "{class_name} error at deserialization: {errors.join(", ")}"
			return null # Let's be safe
		end

		return deserialized
	end