Singleton class in Python

singleton.py

#http://elbenshira.com/blog/singleton-pattern-in-python/
#http://stackoverflow.com/questions/6760685/creating-a-singleton-in-python

def singleton(cls):
    instances = {}
    def getinstance():
        if cls not in instances:
            instances[cls] = cls()
        return instances[cls]
    return getinstance

class Counter:
    def __init__(self):
        self.count = 0
    def inc(self):
        self.count += 1

print type(Counter)    # <type 'classobj'>
Counter = singleton(Counter)
print type(Counter)