code: def normframe(I: np.ndarray, Clim: tuple) -> np.ndarray:
      
      Vmin = Clim[0]
      Vmax = Clim[1]
  
      # stretch to [0,1]
      return (I.astype(np.float32).clip(Vmin, Vmax) - Vmin) / (Vmax - Vmin)
docs: inputs:
      -------
      I: 2-D Numpy array of grayscale image data
      Clim: length 2 of tuple or numpy 1-D array specifying lowest and highest expected values in grayscale image