what flask is used for code example

Example 1: what is flask

These are by far the best Flask tutorials there are: https://youtube.com/playlist?list=PLzMcBGfZo4-n4vJJybUVV3Un_NFS5EOgX

Example 2: what is flask

Flask is a web framework written in Python. 
This means flask provides you with tools, libraries and technologies that allow you to build a web application.

Here a a few resources for learning Flask (I have not personally used them before):
	https://youtube.com/playlist?list=PLzMcBGfZo4-n4vJJybUVV3Un_NFS5EOgX
    https://realpython.com/tutorials/flask/
    https://opensource.com/article/18/4/flask