public function testRemove()
 {
     $collection = new Collection(['a' => 'y', 'b' => 'Y', 'c' => 'y']);
     $collection->remove('y', true);
     $this->assertEquals(['b' => 'Y'], $collection->toArray());
     $collection->remove('this should not have any effect');
     $collection->remove('y');
     $this->assertEquals([], $collection->toArray());
 }