rospy: Cannot locate rosdep definition for [catkin]

If you are encountering the error "Cannot locate rosdep definition for [catkin]" while trying to resolve the `rospy` dependency, you can follow these steps to resolve the issue:

1. Make sure that you have installed the `rosdep` package. If not, you can install it by running the following command:

   sudo apt-get install python-rosdep

2. Run the `rosdep init` command to initialize `rosdep`:

   sudo rosdep init

3. Update `rosdep` by running the following command:

   rosdep update

4. Next, run the following command to resolve the `catkin` dependency:

   rosdep install catkin

5. Finally, try to resolve the `rospy` dependency again by running:

   rosdep install rospy

By following these steps, you should be able to resolve the "Cannot locate rosdep definition for [catkin]" error and successfully locate the `rosdep` definition for `rospy`.