protected function parseSingleRelationship(string $relation): bool
    {
        if (!$value = $this->parseForCommonValues($relation)) {
            return true;
        }

        if ($value instanceof Collection || is_array($value) || $value instanceof CollectionProxy) {
            throw new MappingException("Entity's attribute $relation should not be array, or collection");
        }

        if ($value instanceof LazyLoadingInterface && !$value->isProxyInitialized()) {
            $this->relationships[$relation] = [];

            return true;
        }

        // If the attribute is a loaded proxy, swap it for its
        // loaded entity.
        if ($value instanceof LazyLoadingInterface && $value->isProxyInitialized()) {
            $value = $value->getWrappedValueHolderValue();
        }

        if ($this->isParentOrRoot($value)) {
            $this->relationships[$relation] = [];

            return true;
        }

        // At this point, we can assume the attribute is an Entity instance
        // so we'll treat it as such.
        $subAggregate = $this->createSubAggregate($value, $relation);

        // Even if it's a single entity, we'll store it as an array
        // just for consistency with other relationships
        $this->relationships[$relation] = [$subAggregate];

        // We always need to check a loaded relation is in sync
        // with its local key
        $this->needSync[] = $relation;

        return true;
    }