Questions about private access control in php classes

class Bar
{
public function test() {
$this->testPrivate();
$this->testPublic();
}
public function testPublic() {
echo "Bar::testPublicn";
}
private function testPrivate() {
echo "Bar::testPrivate";
}
}
class Foo extends Bar
{
public function testPublic() {
echo "Foo: :testPublicn";
}
private function testPrivate() {
echo "Foo::testPrivaten";
}
}
$myFoo = new foo();
$myFoo->test(); // Bar:: testPrivate
// Foo::testPublic

Why does Bar::testPrivate appear in the first line? some documents: Contents of 7 in this folder

On the PHP official website, the contributors about this code responded: http://www.php.net/manual/zh/language.oop5.visibility.php#87413