code: def _read(self):
          
          self.json_file.seek(0)
          try:
              data = zlib.decompress(self.json_file.read())
              self.backup_dict = json.loads(data.decode('utf-8'))
          except (EOFError, zlib.error):
              self.backup_dict = {}
docs: Reads backup file from json_file property and sets backup_dict property
          with data decompressed and deserialized from that file. If no usable
          data is found backup_dict is set to the empty dict.