New submission from Беатрис Бонева :
When changing a dict while iterating through it by removing one key and
inserting other which is calculated based on the old one, the dict is changed
unexpectedly.
The following function:
```
def test(d: dict):
for i in d:
d[i+1] = d.pop(i
New submission from Беатрис Бонева :
The select function does not work for file descriptors with number >= 1024. It
has FD_SETSIZE limit (see
https://stackoverflow.com/questions/7976388/increasing-limit-of-fd-setsize-and-select#7977082).
So, serve_forever won't work if more than 1
