Cannot import my self-defined msg in ROS using Python

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Hi everyone,

I'm quite new in programming using Python, but I need to use it in order to call some libraries in ROS I've downloaded from Github. The thing is that I need to call a msg I've created (it works in ROS using C++), but when I try to load it in a Python script using from my_pkg.msg import my_msg it just exit because of the following error:

ImportError: No module named msg

I've followed the instruction you can find in this tutorial 1 and I've read a lot of topics, but I still cannot solve it. The thing is that for what I can understand from other topics and user answer, Python makes itself a mess and cannot find the module. There's something I might be forgeting. Any idea?