'Is the value of the underlying PyObject* visible to the debugger?
This can vary with the precise version of the compiler used to build
Python, and the precise version of gdb.
See e.g. https://bugzilla.redhat.com/show_bug.cgi?id=556975 with
PyEval_EvalFrameEx\'s "f"'

def is_optimized_out(self):

    return self._gdbval.is_optimized_out
