Editing and testing a package

[amasta]

Hello, I found a Python package on Github that I want to modify and use for my own application. How can I best edit such a package. I've installed it using pip. Until now I edited the files in the ../site-packages/ folder, but I learned that this is not a good practice. I've made a fork in Github and edit this source code. I am using Spyder to test the code. But Spyder only imports packages from the Anaconda folder, not the Github folder.

I am a beginner in python, but what is the best practice to do this task?