apache-arrow

We can add to a highlevel array with a record, e.g.

a = ak.Array({"x": [1, 2, 3], "y": [4, 5, 6]})
a["z"] = [7, 8, 9]

but we can't delete:

del a["z"]  # AttributeError
a["z"] = None  # makes a numpy object array

It would be helpful to have Fletchgen output warnings for unused metadata fields that start with fletcher_. For example, (this happened to me) when someone adds fletchgen_epc to Schema metadata instead of Field metadata.