'boolean', 'start_date' => 'date', 'end_date' => 'date', ]; public function course(): BelongsTo { return $this->belongsTo(Course::class); } public function organization(): BelongsTo { return $this->belongsTo(Organization::class); } public function group(): BelongsTo { return $this->belongsTo(Group::class); } public function user(): BelongsTo { return $this->belongsTo(User::class); } public function creator(): BelongsTo { return $this->belongsTo(User::class, 'created_by'); } }