docs: def stepback(self, append=False):
          """
          Stepbacks/reverses the buffer.
          Optional arguments:
          * append=False - If True, appends the data onto the buffer;
                          else, it just steps the index back.
          """
          if append:
              data = self._buffer[self._index - 1]
              self._buffer.append(data)
          else:
              self._index -= 1