src/Registry/DoctrineOrmManagerRegistry.php
public function getManager($name = null): ObjectManager
    {
        $this->loadManagers();

        $name = $name ?? $this->getDefaultManagerName();

        if (!isset($this->originalManagers[$name])) {
            throw new \InvalidArgumentException(sprintf('Missing manager with name "%s".', $name));
        }

        if (isset($this->resetedManagers[$name])) {
            return $this->resetedManagers[$name];
        }

        return $this->originalManagers[$name];
    }
public function getManager($name = null): ObjectManager
    {
        $this->loadManagers();

        $name = $name ?? $this->getDefaultManagerName();

        if (!isset($this->originalManagers[$name])) {
            throw new \InvalidArgumentException(sprintf('Missing manager with name "%s".', $name));
        }

        if (isset($this->resetedManagers[$name])) {
            return $this->resetedManagers[$name];
        }

        return $this->originalManagers[$name];
    }
@param string|null $name

@return EntityManager|ObjectManager