mysum.py - incorrect import of type Iterable from collections package

the code incorrectly imports collections.Iterable, instead of typing.Iterable. This error is not caught for python 3.9+ because of interpreter changes But for python 3.8, the code throws error - ``` $ python mysum.py Traceback (most recent call last): File "mysum.py", line 10, in <module> def sum(it: Iterable[T]) -> Union[T, int]: ... # <2> ```

15-more-types/mysum.py

@@ -1,7 +1,6 @@
 import functools
 import operator
-from collections.abc import Iterable
-from typing import overload, Union, TypeVar
+from typing import overload, Union, TypeVar, Iterable
 
 T = TypeVar('T')
 S = TypeVar('S') # <1>