It applies to Python, Ruby, and other languages all the same. Adding a library relinquishes control over bugs to third parties. This is very, very costly once a

It applies to Python, Ruby, and other languages all the same. Adding a library relinquishes control over bugs to third parties. This is very, very costly once a bug happens, because you can't just fix the issue and be done with it. You need to make a patch and make it to the upstream, or you need to patch the library and manage that.