|  | @@ 278-293 (lines=16) @@ | 
                                                            
                                    | 275 |  |      * | 
                                                            
                                    | 276 |  |      * @return object|null The related resource if found else null | 
                                                            
                                    | 277 |  |      */ | 
                                                            
                                    | 278 |  |     public function getRelatedResourceReference( | 
                                                            
                                    | 279 |  |         ResourceSet $sourceResourceSet, | 
                                                            
                                    | 280 |  |         $sourceEntityInstance, | 
                                                            
                                    | 281 |  |         ResourceSet $targetResourceSet, | 
                                                            
                                    | 282 |  |         ResourceProperty $targetProperty | 
                                                            
                                    | 283 |  |     ) { | 
                                                            
                                    | 284 |  |         if (!($sourceEntityInstance instanceof Model)) { | 
                                                            
                                    | 285 |  |             throw new InvalidArgumentException('Source entity must be an Eloquent model.'); | 
                                                            
                                    | 286 |  |         } | 
                                                            
                                    | 287 |  |         $this->checkSourceInstance($sourceEntityInstance); | 
                                                            
                                    | 288 |  |  | 
                                                            
                                    | 289 |  |         $this->checkAuth($sourceEntityInstance); | 
                                                            
                                    | 290 |  |  | 
                                                            
                                    | 291 |  |         $propertyName = $targetProperty->getName(); | 
                                                            
                                    | 292 |  |         return $sourceEntityInstance->$propertyName; | 
                                                            
                                    | 293 |  |     } | 
                                                            
                                    | 294 |  |  | 
                                                            
                                    | 295 |  |     /** | 
                                                            
                                    | 296 |  |      * Gets a related entity instance from an entity set identified by a key | 
                                                                                
                                |  | @@ 307-319 (lines=13) @@ | 
                                                            
                                    | 304 |  |      * | 
                                                            
                                    | 305 |  |      * @return object|null Returns entity instance if found else null | 
                                                            
                                    | 306 |  |      */ | 
                                                            
                                    | 307 |  |     public function getResourceFromRelatedResourceSet( | 
                                                            
                                    | 308 |  |         ResourceSet $sourceResourceSet, | 
                                                            
                                    | 309 |  |         $sourceEntityInstance, | 
                                                            
                                    | 310 |  |         ResourceSet $targetResourceSet, | 
                                                            
                                    | 311 |  |         ResourceProperty $targetProperty, | 
                                                            
                                    | 312 |  |         KeyDescriptor $keyDescriptor | 
                                                            
                                    | 313 |  |     ) { | 
                                                            
                                    | 314 |  |         if (!($sourceEntityInstance instanceof Model)) { | 
                                                            
                                    | 315 |  |             throw new InvalidArgumentException('Source entity must be an Eloquent model.'); | 
                                                            
                                    | 316 |  |         } | 
                                                            
                                    | 317 |  |         $propertyName = $targetProperty->getName(); | 
                                                            
                                    | 318 |  |         return $this->getResource(null, $keyDescriptor, [], $sourceEntityInstance->$propertyName); | 
                                                            
                                    | 319 |  |     } | 
                                                            
                                    | 320 |  |  | 
                                                            
                                    | 321 |  |  | 
                                                            
                                    | 322 |  |     /** |