Class 6 not compile (ros2 components)

Despite i follow all the instructions of the tutorial of 6.1 exercise the program does not compile. I think there is some trouble with the cmake list example.
When i make colcon build this is the output:

CMake Error at CMakeLists.txt:26 (find_package):
By not providing “Findpub_topic.cmake” in CMAKE_MODULE_PATH this project
has asked CMake to find a package configuration file provided by
“pub_topic”, but CMake did not find one.

Could not find a package configuration file provided by “pub_topic” with
any of the following names:


Add the installation prefix of “pub_topic” to CMAKE_PREFIX_PATH or set
“pub_topic_DIR” to a directory containing one of the above files. If
“pub_topic” provides a separate development package or SDK, be sure it has
been installed.

Hello @joaquinrestovich96 ,

You are in Unit 6 - Node Composition, right? The error says that it’s looking for a package named pub_topic, which can’t be found in your workspace. Probably you have this package listed as a dependency in your CMakeLists.txt/package.xml files. If you remove this dependency, the error will be gone.