protected function _relation($classType, $key, $data, $options = []) {
		return parent::_relation($classType, $key, $data, ['exists' => false] + $options);
	}
protected function _relation($classType, $key, $data, $options = []) {
		return parent::_relation($classType, $key, $data, ['exists' => false] + $options);
	}
protected function _relation ( $ classType , $ key , $ data , $ options = [ ] ) { return parent :: _relation ( $ classType , $ key , $ data , [ 'exists' => false ] + $ options ) ; }
Instantiates a new `Document` object as a descendant of the current object, and sets all
default values and internal state.

@param string $classType The type of class to create, either `'entity'` or `'set'`.
@param string $key The key name to which the related object is assigned.
@param array $data The internal data of the related object.
@param array $options Any other options to pass when instantiating the related object.
@return object Returns a new `Document` object instance.
Instantiates a new Document object as a descendant of the current object and sets all default values and internal state .