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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def items(self):
 		""" 		Generator returning all keys and values stored in a trie. 		"""


		L = []
		def aux(node, s):
			s = s + node.char
			if node.output is not nil:
				L.append((s, node.output))

			for child in node.children.values():
				if child is not node:
					aux(child, s)

		aux(self.root, '')
		return iter(L)