lemiant

import threading
class ReadWriteLock(object):
    """ An implementation of a read-write lock for Python. 
    Any number of readers can work simultaneously but they 
    are mutually exclusive with any writers (which can 
    only have one at a time).
    
    This implementation is reader biased. This can be harmful
    under heavy load because it can starve writers.
    However under light load it will be quite perfomant since