# Find values stored under `prefix`
	#
	# ~~~
	# # Associate some integers to Map keys
	# var trie = new Trie[Int]
	# trie["foo"] = 1
	# trie["bar"] = 4
	# trie["baz"] = 5
	#
	# assert trie.has_prefix("")
	# assert trie.has_prefix("f")
	# assert not trie.has_prefix("z")
	# ~~~
	fun has_prefix(prefix: String): Bool do
		if prefix == "" then return true
		return search_node(prefix) != null
	end