Where can I download the codes used in the course?
The code that you have entered in course exercises cannot be downloaded. You can, however, access it at any time by navigating directly to the exercises where you entered it and copying and pasting it to a secure location.
If you are looking for the Datasets used in the course, they can be found directly from the course homepage. For example, while navigating to the bottom of the Python Data Science Toolbox (Part 1) course, you will see a section called Datasets. You can download it as a file by right-clicking on it and "Saving the link as...".