import sys

def gen():
    yield 1
    yield 2

def callback(code, off, exc):
    if code is gen.__code__:
        print("got unwind!")

ID=3
sysmon = sys.monitoring
sysmon.use_tool_id(ID, "test")
sysmon.register_callback(ID, sysmon.events.PY_UNWIND, callback)
sysmon.set_events(ID, sysmon.events.PY_UNWIND)

g = gen()
next(g)
del g  # or g.close()