# Match documents where `field` is in `values`
	#
	# https://docs.mongodb.com/manual/reference/operator/query/in/
	#
	# ~~~json
	# { field: { $in: [<value1>, <value2>, ... <valueN> ] } }
	# ~~~
	#
	# `$in` selects the documents where the value of a field equals any value
	# in the specified array.
	fun is_in(field: String, values: Array[nullable Serializable]): MongoMatch do
		op("in", field, new JsonArray.from(values))
		return self
	end