Return the items of the dictionary sorted by the keys

	>>> sample = dict(foo=20, bar=42, baz=10)
	>>> tuple(sorted_items(sample))
	(('bar', 42), ('baz', 10), ('foo', 20))

	>>> reverse_string = lambda s: ''.join(reversed(s))
	>>> tuple(sorted_items(sample, key=reverse_string))
	(('foo', 20), ('bar', 42), ('baz', 10))

	>>> tuple(sorted_items(sample, reverse=True))
	(('foo', 20), ('baz', 10), ('bar', 42))

def sorted_items(d, key=__identity, reverse=False):
	"""
	Return the items of the dictionary sorted by the keys

	>>> sample = dict(foo=20, bar=42, baz=10)
	>>> tuple(sorted_items(sample))
	(('bar', 42), ('baz', 10), ('foo', 20))

	>>> reverse_string = lambda s: ''.join(reversed(s))
	>>> tuple(sorted_items(sample, key=reverse_string))
	(('foo', 20), ('bar', 42), ('baz', 10))

	>>> tuple(sorted_items(sample, reverse=True))
	(('foo', 20), ('baz', 10), ('bar', 42))
	"""
	# wrap the key func so it operates on the first element of each item
	def pairkey_key(item):
		return key(item[0])
	return sorted(d.items(), key=pairkey_key, reverse=reverse)