def save_snaphot(self):
filename = "<STR_LIT>" % (self.snapshot_path, self.name, self.expiration, self.date)<EOL>with open(filename, '<STR_LIT:w>') as f:<EOL><INDENT>f.write(zlib.compress(pickle.dumps(self.current_day_bitarray, protocol=pickle.HIGHEST_PROTOCOL)))<EOL><DEDENT>
Save the current state of the current day bitarray on disk.

        Save the internal representation (bitarray) into a binary file using this format:
            filename : name_expiration_2013-01-01.dat