error in import

Dear ROS-Users I created a service in my_package but I am not able to import it. In particular, using "from my_package import srv" in a ros-python node raise me this error: ImportError: cannot import name srv However, doing the same "from my_package import srv" from a python shell, I don't get any error I'm using catkin on ros-hydro and both catkin_make and catkin_make install don't give me any erro Thank you for your help