printing `af.tree.keys()` prints the whole tree

[Cadair]

with asdf.open(filename) as af:
    print(af.tree.keys())

Instead of just printing the keys it prints (presumably) both the keys and the str representation of the whole tree which is super unhelpful when you are trying to interactively explore a tree.

[braingram]

FWIW this is the same behavior for any KeysView:

>> import collections
>> d = collections.UserDict({"a": {"b": {"c": [1, 2, 3]}}})
>> d.keys()
KeysView({'a': {'b': {'c': [1, 2, 3]}}})

See python/cpython#76481 for discussion of changes to cpython.

Would list(af.tree.keys()) or sorted(af.tree.keys()) be closer to what you're expecting?

[Cadair]

I've been using list(af.tree.keys()) in my repl. Printing the whole massive dict is very unhelpful.