Setting up Environment:
BeautifulSoup: pip install beautifulsoup4
mechanize: pip install mechanize
pdfkit :pip install pdfkit
pdfkit needs wkhtmltopdf to work .[Instructions] (https://pypi.python.org/pypi/pdfkit)
Run again if some error occurs. It wont replace pre-existing files and will only download the ones that haven't been downloaded yet.