Unit 2 topics exercise 2.2

Hi @abhinavabhi742,

I did not find any problem with this package itself. Just that catkin_make did not complete at first because of the custom_service package, which was preventing catkin_make from completing.

I suggest you fix the custom_service package (as hinted on the thread for it), remove build and devel and compile again:

cd ~/catkin_ws/
rm -rf build devel 
catkin_make
source devel/setup.bash # run this on every terminal