Service/PairStorage.php
public function set($key, $value)
    {
        $pair = $this->repository->find($key);
        if ($pair === null) {
            $pair = new Pair();
            $pair->setId($key);
        }

        $pair->setValue($value);
        $this->save($pair);

        return $pair;
    }
public function set($key, $value)
    {
        $pair = $this->repository->find($key);
        if ($pair === null) {
            $pair = new Pair();
            $pair->setId($key);
        }

        $pair->setValue($value);
        $this->save($pair);

        return $pair;
    }
Sets pair value. Returns pair with values.

@param string $key
@param mixed  $value

@return DocumentInterface