Underneath the decorator and the function declaration, the ArenaForm from forms.py is called and the function request.form is passed as a parameter. This adds functionality to the ArenaForm and allows it to access the request's own parameters as needed.
Once the ArenaForm object is passed to the variable form, it can be populated with data. This data will come from an SQLAlchemy session query on the Arena model. This query requests all rows of data from the Arena table and passes it to the variable arenas using all method (as opposed to the filter_by method which would limit the rows returned).
Because the ArenaForm's selections field is currently blank, we'll use a list comprehension to loop through the arena objects contained ...
