KeySet class in python is missing methods

[dwiel]

Feature

The KeySet class in python should have more methods available like __iter__, __contains__, remove, etc.

Motivation

I'd like to be able to do things like:

for key in graph.keys():
    if key not in initial_estimate.keys():
        print(f"WARNING: missing key {key} in initial_estimate")

[ProfFan]

Yeah this would be a great extension. We may need some special code to do this though, as KeySet is a bit more than a standard std::set. CC @varunagrawal

[varunagrawal]

I think the easiest way to achieve this is to replace gtsam::KeySet with std::set<gtsam::Key> (aka the superclass) in all the .i files?

[varunagrawal]

A better way to do this is to integrate dunder methods (e.g. __iter__) into our wrapper library gtwrap. @dwiel can you compile a list of all the special methods needed?

[varunagrawal]

Accidentally closed this. This issue will be resolved when we merge #1712.