On: Lily: An interpreted language with a focus on expr...

[wool_gather]

Another option, it's very easy to wrap a dict in a defaultdict:

    class optionaldict(defaultdict):
	"""
	A defaultdict that disregards KeyErrors and returns None for missing keys.
	"""
	def __init__(self, *original, **kwargs):
	    super().__init__(lambda: None, *original, **kwargs)

[Quelklef → wool_gather]

This is almost always a bad idea, though; it doesn't distinguish between

    {k: None}[k]

and

    {}[k]

[bvrmn → wool_gather]

It's not a generic option, you are polluting memory with non-existing keys.