Demonstrate how to use Python's weakref module to ensure that filemagic Magic objects are closed before begin garbage collected when encapsulated inside a container object.

magic_ok.py

import magic
import weakref


class Container(object):

    def __init__(self):
        _magic = magic.Magic()
        cleanup = lambda _: _magic.close()
        self._magic_weakref = weakref.ref(self, cleanup)
        self._magic = _magic


if __name__ == "__main__":
    con = Container()

magic_warning.py

import magic


class Container(object):

    def __init__(self):
        self._magic = magic.Magic()


if __name__ == "__main__":
    con = Container()