docs: def has_duplicate(x):
      """
      Checks if any value in x occurs more than once
  
      :param x: the time series to calculate the feature of
      :type x: numpy.ndarray
      :return: the value of this feature
      :return type: bool
      """
      if not isinstance(x, (np.ndarray, pd.Series)):
          x = np.asarray(x)
      return x.size != np.unique(x).size