Robustness improvements for _dict_utils.py: Handling edge cases and preventing RuntimeErrors

[SalimMessaad1]

Hi there,

I was looking through the utility functions in _dict_utils.py and noticed a few spots where the code might break or behave unexpectedly when hitting certain edge cases. I think adding some defensive checks could save users from some confusing debugging sessions.

Here are the main points I found:

1. Potential RuntimeError in delete_keys
   In the else block of delete_keys, the code iterates over selected_keys and deletes items from the dictionary. If a user passes a live view (like my_dict.keys()), Python will throw a RuntimeError because the dictionary size changes during iteration.

Fix: It’s safer to wrap selected_keys in a list() or set() to ensure we’re iterating over a static snapshot.

2. Brittle sequence/dict conversions

In seq_of_dict_to_dict_of_seq, the code assumes all dictionaries have the same keys as the first one. If they don't, it'll either raise a KeyError or produce mismatched list lengths.
In dict_of_seq_to_seq_of_dict, passing an empty dictionary causes next(iter(values.keys())) to raise a StopIteration error.

Fix: Adding a quick check for empty inputs and ensuring key consistency would make this much more robust.

3. Implicit data loss in rename_keys
   The logic for handling collisions in rename_keys (via the omit set) is clever, but it might surprise users by silently dropping data if they aren't careful with their mapping.

Fix: Maybe a simple warning or just a clearer docstring note about how collisions are handled would help.

I've already played around with some fixes for these. Would you be open to a PR?

Best, Salim