@DrMuhammadAnju1_twitter this (and the other Jupyter-related rooms) is not the appropriate place for general help using Python. You might try Stack Overflow or another Q&A place meant for general help. This is a room for questions about developing or using the IPython package. Upgrading Python will depend on your system and how you installed Python 3.5. Usually the same way you installed one version of Python, you can install another version, whether it is from Python.org, conda, homebrew, or apt-get.