def load(self):

        dd = self._session_key.split("--")

        # make sure we got both elements
        if len(dd) == 2:
            data = re.sub('%3D','=',dd[0])
            # now make sure digest is valid
            if dd[1] == self.generate_digest(data):
                # valid. decode and load data
                decoded_data = base64.b64decode(data)

                # First load with YAML, if there is a YAML syntax error, then load with JSON
                try:
                    print "trying yaml..."
                    obj = yaml.load(decoded_data)
                except ValueError:
                    print "trying json..."
                    obj = simplejson.loads(decoded_data)
                except:
                    print "Couldn't load data. A new session will be created."
                    obj = False

                if obj:
                    print "got object"
                    # intercept _session_expiry
                    if obj.has_key("_session_expiry"):
                        obj['_session_expiry'] = datetime.datetime.fromtimestamp(int(obj['_session_expiry']))
                    return obj
                else:
                    # if we get here, it was invalid and we should generate a new session
                    self.create()
                    return {}


    def _get_session_key(self):

        obj = getattr(self, '_session_cache', {})

        # intercept _session_expiry
        if obj.has_key("_session_expiry") and isinstance(obj['_session_expiry'],datetime.datetime):
            obj['_session_expiry'] = obj['_session_expiry'].strftime("%s")

        # add session_id if it's not present
        if not obj.has_key("session_id"):
            obj['session_id'] = rand.bytes(16).encode('hex_codec')

        # Dump to YAML, then encode as base64
        enc = base64.b64encode(yaml.dump(obj))

        return "--".join([re.sub('=','%3D',enc),self.generate_digest(enc)])