code: def transformation_matrix(self):
          
          t = np.array([[0.0], [0.0], [0.0]])
          Rt = np.hstack([self.rotation_matrix, t])
          return np.vstack([Rt, np.array([0.0, 0.0, 0.0, 1.0])])
docs: Get the 4x4 homogeneous transformation matrix equivalent of the quaternion rotation.
  
          Returns:
              A 4x4 homogeneous transformation matrix as a 4x4 Numpy array
  
          Note:
              This feature only makes sense when referring to a unit quaternion. Calling this method will implicitly normalise the Quaternion object to a unit quaternion if it is not already one.