code: def get_token(self):
          
          token = None
          if self.token_path.exists():
              with self.token_path.open('r') as token_file:
                  token = self.token_constructor(self.serializer.load(token_file))
          self.token = token
          return token
docs: Retrieves the token from the File System
          :return dict or None: The token if exists, None otherwise