[graph-tool] Is it possible to work with legacy structures

I am currently working with a code that has a directed graph structure: an object defines `inputs` and `outputs` which return iterables of the objects with the same interface. Each object has a bunch of useful payload. I am looking for a python libarary that is capable of handling such data structure without the conversion to an intermediate format that is loaded for graph processing algrorithms.

So instead of walking the data structure I have and converting it to a list of lists or whatever representation is consumed by the graph library, I would specify an adaptor interface to my own class so the graph library would be able to interact with my hierarchy directly. Is this sort of thing possible?

Best regards, Anton