/**
  * @inheritdoc
  */
 public function containsKey($key)
 {
     if (!is_int($key)) {
         throw InvalidArgumentException::invalidType('key', 'integer', $key);
     }
     return isset($this->items[$key]);
 }
 /**
  * @test
  */
 public function it_creates_an_invalidTypeInArray_exception_mentioning_the_type_of_an_object()
 {
     $exception = InvalidArgumentException::invalidTypeInArray('someArgument', 'string', new stdClass());
     $this->assertInstanceOf(InvalidArgumentException::class, $exception);
     $this->assertSame('Each value in argument $someArgument must be of type string, stdClass given', $exception->getMessage());
 }