def get_chain(d):
	nodes = {}
	# create linked list nodes
	for name, (end, start) in d.items():
		nodes[start] = [name, (start, end), None]
 
	# build the linked list by looking up other nodes
	for node in list(nodes.values()):
		start, end = node[1]
		node[2] = nodes.pop(end, None)
 
	# there should be only a single node left in nodes
	head = next(iter(nodes.values()), None)
 
	# yield out the chain values
	while head is not None:
		start, end = head[1]
		yield start
		# if last node, yield the end value
		if head[2] is None:
			yield end
		head = head[2]
 
print(list(get_chain({
	'A': ['tg', 17], 
	'B': [59, 60], 
	'C': [60, 61], 
	'D': [57, 'tt'], 
	'E': [61, 'tg'], 
	'F': ['tt', 59]
})))

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