# Search `key` with a distance of `tolerance` in `self`.
	#
	# If `tolerance` is null, the use `default_tolerance` instead.
	fun search(key: String, tolerance: nullable Int): Array[BKMatch] do
		var res = new Array[BKMatch]
		var root = self.root
		if root != null then
			if tolerance == null then tolerance = self.default_tolerance
			search_recursive(root, res, key, tolerance)
		end
		default_comparator.sort(res)
		return res
	end