I run:
pip install dstk --user --allow-external dstk --allow-unverified dstk
And get:
dstk is potentially insecure and unverifiable. HTTP error 403 while getting http://www.datasciencetoolkit.org/dstk-0.50.tar.gz (from https://pypi.python.org/simple/dstk/) Could not install requirement dstk from http://www.datasciencetoolkit.org/dstk-0.50.tar.gz because of error 403 Client Error: Forbidden Could not install requirement dstk from http://www.datasciencetoolkit.org/dstk-0.50.tar.gz because of HTTP error 403 Client Error: Forbidden for URL http://www.datasciencetoolkit.org/dstk-0.50.tar.gz (from http s://pypi.python.org/simple/dstk/)
Note: this command did work on my paid account.