def get_students_by_promo(wrapper, promo: int) ->list:
    """Get list of student by promo."""
    student_list = []
    students = wrapper.get_students(promotion_id=promo)
    if 'does not exist' in students:
        print('Promo ID does not exist')
        return None
    for student in students['students']:
        student_list.append(student['login'])
    return student_list
