Expose `select_columns` to the public interface against my
better judgment.
Plural please.
Provide a sensible default ordering for plays and drives when
accessed via their respective attributes.
It would be nice to terminate.
Better AttributeError exception message.
Typo bug.
Make PossessionTime consistent with Clock and FieldPosition.
The magic __add__ method should be able to handle integers.
Spacing? Whoops.