A simple distributed lock with memcached... in Python

Following Sylvain's advice I just wrote a memcache lock in Python:

class Lock():
   def __init__(self, key):
       self.key = "lock.%s" % key

   def __enter__(self):
       while True:
           value = getClient().add(self.key, "1", 60000)
           if value == True:
               return
           time.sleep(.1)

   def __exit__(self, exc_type, exc_val, exc_tb):
       getClient().delete(self.key)
       return False

Using the lock is as simple as doing:

with Lock("critical1"):
   doSomeExpensiveStuff()

The advantage over Sylvain's Java version is that the locking code is reusable, thanks to the use of a Python context manager.