[Python] How can I efficiently map and update frequencies of nested items using dictionaries...

I'm working on a small DSA practice problem involving frequency counting, but with a twist.
I have a list of tuples where each tuple represents a (category, item). Example:

data = [
("fruit", "apple"),
("fruit", "banana"),
("veg", "carrot"),
("fruit", "apple"),
("veg", "carrot"),
("veg", "tomato"),
]


I want to build a dictionary that looks like this:

{
"fruit": {"apple": 2, "banana": 1},
"veg": {"carrot": 2, "tomato": 1}
}



I can do this with nested loops or by checking keys manually, but my code feels messy.

Is there a cleaner or more Pythonic way to build and update a nested dictionary like this? Bonus points if it handles missing keys gracefully without throwing KeyErrors.

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