https://www.cnblogs.com/xybaby/p/7491656.html

# -*- coding: utf-8 -*-
import objgraph

_cache = []

class OBJ(object):
    pass

def func_to_leak():
    o  = OBJ()
    _cache.append(o)
    # do something with o, then remove it from _cache 

    if True: # this seem ugly, but it always exists
        return 
    _cache.remove(o)

if __name__ == '__main__':
    objgraph.show_growth()
    try:
        func_to_leak()
    except:
        pass
    print 'after call func_to_leak'
    objgraph.show_growth()