This has been discussed previously, (and it’s often mentioned in other discussions too):
- Add the ability to declare an empty dict as `{:}`
- Mailman 3 Empty set {} and empty dict {:} ? - Python-ideas - python.org
- Mailman 3 Possible method of distinguishing between set-literals, dict-literals, and odict-literals - Python-ideas - python.org
- Mailman 3 syntax for set - Python-ideas - python.org
- Mailman 3 Re: [Python-ideas] Empty set, Empty dict - Python-ideas - python.org
- Mailman 3 Sets, Dictionaries - Python-ideas - python.org
- Mailman 3 Adding syntax for the empty set - Python-ideas - python.org
- Mailman 3 An unambiguous way of initializing an empty set and dictionary - Python-ideas - python.org
You can {*()} as a workaround, although you do start to wonder if {*} would make sense.