When "TypeError: Cannot instantiate typing.*" appears, it seems to be about using parentheses instead of brackets. Still, I'm curious about why Python exhibits the following behavior: from typing import Final def f(): h : Final[int] = 10 # Accepted i : Final(int) = 15 # Accepted f() # Ran successfully j : Final[int] = 1 # Accepted k : Final(int) = 2 # ERROR Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/lib/python3.9/typing.py", line 335, in __call__ raise TypeError(f"Cannot instantiate {self!r}") TypeError: Cannot instantiate typing.Final Why is it either-or inside function definitions, but not the main block? Continue reading...
