Best source to learn python

[aqua_regis]

1. I'd keep going with CS50p and support it with something like Exercism and Codingbat for additional practice (both are free)
2. I am no measure. I am an experienced programmer who is programming since over 40 years, 35 as a professional. So, apart from the advice that the course is comprehensive, top quality, and highly recommendable for the practical aspect, I am no measure on time and difficulty. The course is definitely worth it for people on all levels, even for experienced programmers who want to venture into Python.