ImportError: No module named pyquaternion

[spy0529]

Hello！When I rosrun ur_control sim_controller_examples.py -m,there is a mistake.
Traceback (most recent call last):
File "/home/spy/ros_ws/src/ur3/ur_control/scripts/sim_controller_examples.py", line 27, in
from ur_control import transformations, traj_utils, conversions
File "/home/spy/ros_ws/src/ur3/ur_control/src/ur_control/transformations.py", line 175, in
from pyquaternion import Quaternion
ImportError: No module named pyquaternion
How can I save it?
Looking forward your request.

[cambel]

Hi,

Could you install the following package and try again?

pip install pyquaternion