Function: Get course raw price

Filter Hook: Filter the course price from the function dozent_get_course_price();

Function: Get the course formatted price.

Filter Hook: Filter course price free text

Filter Hook: Filter the course formatted price

Function: Determine if enrolled to a course

Function: Enrol an user to a specific course by given course_id | Course Object

Filter Hook: Filter enrolment status which return by the dozent_enrol_course(); function

Function: Return Enrolment class instance

Function: Check course attached product type