protected function findFactoryMethod(
        ReflectionClass $reflectedFactoryClass,    
        MethodSelector $factoryMethodSelector
    ) {
        $allMatchingMethods = $this->findMatchingMethods(
            $reflectedFactoryClass,
            $factoryMethodSelector
        );
        $this->throwExceptionIfWrongNumberOfFactoryMethods($allMatchingMethods);
        return $allMatchingMethods[0];
    }