Function: Get all enrolled courses by specific user

Function: Get all enrolled courses ids

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

Function: Check course attached product type

Function: Return Enrolment class instance

Function: Course access methods, this function returns all available methods

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

Function: Determine if enrolled to a course

Filter Hook: Filter the course formatted price

Filter Hook: Filter course price free text