You have to change path to save file according to requirement. Default path is '/home/amit/Documents'(my Documents directory path)
If you run program from terminal .
first change the directory to where you have saved the ScrapeMedium folder.
eg I have saved it in Desktop so cd Desktop/ScrapeMedium.
After that python scrapemedium.py [link].
eg python scrapemedium.py https://medium.com/@rajaraodv/a-guide-for-building-a-react-redux-crud-app-7fe0b8943d0f#.kb92wj9p6