Simple Request caching to file, for python requests module

reqcache.py

import pickle
import hashlib
import requests

#Make sure the cache directory exists

class CachedSession(requests.Session):
    cache_format = "{cache_dir}/res_{hash}_obj.bin"
    cache_dir = "./cache"

    def send_cached(self, request):
        req_pkl = pickle.dumps(request)
        req_hash = hashlib.sha1(req_pkl).hexdigest()
        cache_file_name = self.cache_format.format(cache_dir = self.cache_dir, hash = req_hash)
        try:
            with open(cache_file_name, "rb") as f:
                return pickle.load(f)
        except (FileNotFoundError, EOFError):
            prep = self.prepare_request(request)
            res = None
            try:
                res = self.send(prep)
                with open(cache_file_name, "wb") as f:
                    pickle.dump(res, f)
            finally:
                return res

#Example usage
if __name__ == "__main__":
    sess = CachedSession()
    request = requests.Request('GET', 'https://www.google.com/')
    res = sess.send_cached(request)
    print("Got data:")
    print(res.text)