Miss annotation, but no NameError?

Happy Halloween! guys

Thank you very much. Now I understood what Python is doing.

>>> a:1
>>> a
Traceback (most recent call last):
  File "<input>", line 1, in <module>
NameError: name 'a' is not defined
>>> __annotations__
{'a': 1}

Still, it’s a bit confusing for me (it looks like the “expression assignment” of maxima).
I must add mypy to my emacs.