code: def mad(var, constant=1):
      
      median = np.median(var)
      mad = np.median(np.abs(var - median))
      mad = mad*constant
      return(mad)
docs: Median Absolute Deviation: a "robust" version of standard deviation.
  
      Parameters
      ----------
      var : list or ndarray
          Value array.
      constant : float
          Scale factor. Use 1.4826 for results similar to default R.
  
      Returns
      ----------
      mad : float
          The MAD.
  
      Example
      ----------
      >>> import neurokit as nk
      >>> hrv = nk.mad([2, 8, 7, 5, 4, 12, 5, 1])
  
      Notes
      ----------
      *Authors*
  
      - `Dominique Makowski <https://dominiquemakowski.github.io/>`_
  
      *Dependencies*
  
      - numpy
  
      References
      -----------
      - https://en.wikipedia.org/wiki/Median_absolute_deviation