public function testIntersectsBooleanFlag()
 {
     $a = array('foo', 'bar');
     $b = array('bar', 'baz');
     $this->assertTrue(Arrays::intersects($a, $b));
     $a = 'bar';
     $this->assertTrue(Arrays::intersects($a, $b));
     $a = 'foo';
     $this->assertFalse(Arrays::intersects($a, $b));
 }