code: def scale(s, dtype=None):
      
      assert len(s) == 3
      return np.array(np.diag(np.concatenate([s, (1.,)])), dtype)
docs: Non-uniform scaling along the x, y, and z axes
  
      Parameters
      ----------
      s : array-like, shape (3,)
          Scaling in x, y, z.
      dtype : dtype | None
          Output type (if None, don't cast).
  
      Returns
      -------
      M : ndarray
          Transformation matrix describing the scaling.