RuntimeError: Set changed size during iteration

[seddonym]

Certain methods return sets from the graph's internals, e.g.

• find_modules_directly_imported_by

If the graph is mutated while iterating through these sets, this can can a RuntimeError, e.g.

for imported_module in graph.find_modules_directly_imported_by("foo"):
   graph.remove_import(importer="foo", imported=imported_module)

This can be mitigated by copying the set before iterating over it, e.g.

for imported_module in graph.find_modules_directly_imported_by("foo").copy():
   graph.remove_import(importer="foo", imported=imported_module)

But probably it would be better for the method to return a copy.