Frame.outer_undeclared is probably bogus

[damz]

In Frame.__init__, you can see:

self.identifiers.outer_undeclared.update(
    parent.identifiers.undeclared -
    self.identifiers.declared
)

Unfortunately, the frame has not been inspected yet, so self.identifiers is just a new object, and self.identifier.declared will always be empty.

[mitsuhiko]

This is no longer used now.