The script downloads a bunch of files of a given type from the given url to the specified directory. For example,
./download.py --url https://people.eecs.berkeley.edu/~keutzer/classes/244fa2005/lectures/ --filetype pdf
downloads all the lecture files end with 'pdf' from the the Prof. Keutzer's lecture webpage https://people.eecs.berkeley.edu/~keutzer/classes/244fa2005/lectures/ to local directory "./data/" (default location if not specified).