'Return the current variant if in the cache, else None.'

def get(self):

    request = cherrypy.serving.request
    self.tot_gets += 1
    uri = cherrypy.url(qs=request.query_string)
    uricache = self.store.get(uri)
    if (uricache is None):
        return None
    header_values = [request.headers.get(h, '') for h in uricache.selecting_headers]
    variant = uricache.wait(key=tuple(sorted(header_values)), timeout=self.antistampede_timeout, debug=self.debug)
    if (variant is not None):
        self.tot_hist += 1
    return variant
