mlk

import sys
from contextlib import contextmanager

def adapter(ob, fenter, fexit):
    nop = lambda: None
    on_enter = getattr(ob, fenter, nop)
    on_exit = getattr(ob, fexit, nop)
    @contextmanager
    def manager():
        on_enter()
        try:
            yield
        finally:
            on_exit()
    return manager()