Students may be excused from attending class on the day of a graded activity or when attendance contributes to a student's grade, for the reasons stated in Section , or other reason deemed appropriate by the student's instructor. Except in the case of the observance of a religious holiday, to be excused the student must notify his or her instructor in writing (acknowledged e-mail message is acceptable) prior to the date of absence if such notification is feasible. In cases where advance notification is not feasible (. accident, or emergency) the student must provide notification by the end of the second working day after the absence. This notification should include an explanation of why notice could not be sent prior to the class. Accommodations sought for absences due to the observance of a religious holiday can be sought either prior or after the absence, but not later than two working days after the absence.
Note: Relationships are updated without exposing the underlying server semantics, such as foreign keys. Furthermore, relationships can be updated without necessarily affecting the related resources. For example, if an article has many authors, it is possible to remove one of the authors from the article without deleting the person itself. Similarly, if an article has many tags, it is possible to add or remove tags. Under the hood on the server, the first of these examples might be implemented with a foreign key, while the second could be implemented with a join table, but the JSON API protocol would be the same in both cases.