ROS2 issue resolved

There has been a common issue where changing the tuning parameters in rqt_plot causes the entire program to crash. This issue can be resolved by changing line 78 of node.py, in the same directory as pid.py. Instead of

return rclpy.parameter.SetParametersResult(successful=True),

it should say

return SetParametersResult(successful=True)

and add 'from rcl_interfaces.msg import SetParametersResult' in the beginning of the code.

- OJ and the group teachers