Mine

<?php 
interface ILiveSchoolElement {}
interface IPeople {}
interface ITeacher extends IPeople {}
interface ILearner extends IPeople {}

abstract class AbstractPeople implements IPeople {}
abstract class AbstractPeopleLiveSchoolElement extends AbstractPeople implements ILiveSchoolElement {}

class Teacher extends AbstractPeopleLiveSchoolElement implements ITeacher {}
class Learner extends AbstractPeopleLiveSchoolElement implements ILearner {}

class Helga extends Learner {}
?>