private function filterMatchingDefinitions(array $definitions, $objectType)
    {
        return array_filter($definitions, function (Definition $definition) use ($objectType) {
            return strtolower($definition->getObjectType()) === strtolower($objectType) || null === $objectType;
        });
    }
private function filterMatchingDefinitions(array $definitions, $objectType)
    {
        return array_filter($definitions, function (Definition $definition) use ($objectType) {
            return strtolower($definition->getObjectType()) === strtolower($objectType) || null === $objectType;
        });
    }
@param Definition[] $definitions
@param null|string  $objectType

@return Definition[]