Caching does not work with default args

[Kemaweyan]

This code does not work

import requests

dns_cache.override_system_resolver()

for i in range(10):
     requests.get('http://www.coala.io/')

It does not speed up requests but makes them even slowly. Looking into the library code I found that the get method is being called for the dns_cache.hosts.HostsCache object, but the put method calls - for dns_cache.expiration.MinExpirationCache. Of course, it could cache nothing because the self.data dicts are different and the get method could not find items stored in the put method of another object.