php多重接口的实现方法

<?php 
  interface staff_i1 //接口1 
  { 
   function setID($id); 
   function getID(); 
  }   
  interface staff_i2 //接口2 
  { 
   function setName($name); 
   function getName(); 
  }     
  class staff implements staff_i1, staff_i2 //接口的实现 
  { 
   private $id; 
   private $name; 
   function setID($id) 
   { 
     $this->id = $id; 
   } 
   function getID()  
   { 
     return $this->id; 
   } 
   function setName($name)  
   { 
     $this->name = $name; 
   } 
   function getName()  
   { 
     return $this->name; 
   } 
   function otherFunc() 
   { 
    echo "Test"; 
   } 
  } 
?>