old_contents: #!/usr/bin/env python
  import rospy
  
  if __name__ == '__main__':
      pass
  
new_contents: #!/usr/bin/env python
  import rospy
  from trajectory_tracking.srv import TrajectoryPoint, TrajectoryPointResponse
  
  def compute_trajectory(request):
      pass
  
  
  if __name__ == '__main__':
      rospy.init_node('trajectory_server')
      service = rospy.Service('trajectory', TrajectoryPoint, compute_trajectory)
      rospy.spin()
  
subject: Create service trajectory