'date', 'end_date' => 'date', ]; public function courseRequest(): BelongsTo { return $this->belongsTo(CourseRequest::class); } public function course(): BelongsTo { return $this->belongsTo(Course::class); } public function user(): BelongsTo { return $this->belongsTo(User::class); } public function group(): BelongsTo { return $this->belongsTo(Group::class); } public function organization(): BelongsTo { return $this->belongsTo(Organization::class); } public function getTypeAttribute(): string { if ($this->user_id) { return 'individual'; } elseif ($this->group_id) { return 'group'; } return 'organization'; } }