code: def z_score(raw_scores, center=True, scale=True):
      
      df = pd.DataFrame(raw_scores)
  
      mean = df.mean(axis=0)
      sd = df.std(axis=0)
      z_scores = (df - mean)/sd
  
      return(z_scores)
docs: Transform an array, serie or list into Z scores (scaled and centered scores).
  
      Parameters
      ----------
      raw_scores : list, ndarray or pandas.Series
          ECG signal array.
      centered : bool
          Center the array (mean = 0).
      scale :  bool
          scale the array (sd = 1).
  
      Returns
      ----------
      z_scores : pandas.DataFrame
          The normalized scores.
  
  
      Example
      ----------
      >>> import neurokit as nk
      >>>
      >>> nk.z_score([3, 1, 2, 4, 6])
  
      Notes
      ----------
      *Authors*
  
      - `Dominique Makowski <https://dominiquemakowski.github.io/>`_
  
      *Dependencies*
  
      - pandas