code: public function loadRelation(string $name)
      {
          if (!isset($this->relationObjects[$name]) || empty($this->relationObjects[$name])) {
              $relation = $this->getRelations()[$name];
              if (!$relation || !$relation['entity'] || !$this->get($relation['key'] ?? 'id')) {
                  return null;
              }
  
              $entity = $this->entity($relation['entity']);
              $type = $relation['type'] ?? 'has_one';
              $key = $relation['key'] ?? ('has_one' === $type ? $this->__getEntityName().'_id' : 'id');
              $foreignKey = $relation['foreign_key'] ?? ('has_one' === $type ? 'id' : $this->__getEntityName().'_id');
              $assoc = $relation['assoc'] ?? false;
              $this->relationObjects[$name] = ('has_one' === $type) ? $entity->load($this->get($key), $foreignKey) : $entity->loadAll([$foreignKey => $this->get($key)], $assoc);
          }
  
          return $this->relationObjects[$name] ?? null;
      }
docs: Load realated entity by relation name.
  
  @param string $name Relation name
  
  @return null|Collection|Entity