`domain` Option Silently Ignored

[rafatoshio]

Hi,

I noticed an issue in processing_data.py, specifically in the open_dataset.image() function. There is an option called domain, which defaults to None. However, on line 461, the code only checks if domain is an instance of a list or np.ndarray. If domain is any other type, it is silently ignored without raising an error, which can be misleading for users.

I have two suggestions to address this issue:

1 - Update line 461 to check if domain is not None:
if domain is not None

2 - Alternatively, check if domain is an iterable:

from collections.abc import Iterable
if isinstance(domain, Iterable)