Install from PyPI using an installer such as pip:
$ pip install Flask-Session
Unless you are using the FileSystemCache, you will also need to choose and a backend and install an appropriate client library.
For example, if you want to use Redis as your backend, you will need to install the redis-py client library:
$ pip install redis
Supported Backends and Client Libraries¶
Other clients may work if they use the same commands as the ones listed above.