'Takes a ProxyBackend instance or class and wraps the
attached backend.'

def wrap(self, proxy):

    if (type(proxy) == type):
        proxy = proxy()
    if (not issubclass(type(proxy), ProxyBackend)):
        raise TypeError(('Type    %s    is    not    a    valid    ProxyBackend' % type(proxy)))
    self.backend = proxy.wrap(self.backend)
