code: def glover_time_derivative(tr, oversampling=50, time_length=32., onset=0.):
      
      do = .1
      dhrf = 1. / do * (glover_hrf(tr, oversampling, time_length, onset) -
                        glover_hrf(tr, oversampling, time_length, onset + do))
      return dhrf
docs: Implementation of the Glover time derivative hrf (dhrf) model
  
      Parameters
      ----------
      tr: float
          scan repeat time, in seconds
      oversampling: int,
          temporal oversampling factor, optional
      time_length: float,
          hrf kernel length, in seconds
      onset: float,
          onset of the response
  
      Returns
      -------
      dhrf: array of shape(length / tr), dtype=float
            dhrf sampling on the provided grid