redef fun iterator do return new CoupleMapIterator[K,V](couple_iterator)

	redef fun iterator do return map.iterator

	redef fun iterator do return new HashMapIterator[K,V](self)

	# Nodes are iterated in the same order in which they were added to the tree.
	# O(n)
	#
	#     var tree = new BinTreeMap[Int, String]
	#     for i in [4, 2, 1, 5, 3] do tree[i] = "n{i}"
	#     var keys = new Array[Int]
	#     for k, v in tree do
	#         keys.add k
	#     end
	#     assert keys == [4, 2, 1, 5, 3]
	redef fun iterator do return new BinTreeMapIterator[K, E](self)