public function getM2Ps(Criteria $criteria = null, ConnectionInterface $con = null)
    {
        $partial = $this->collM2PsPartial && !$this->isNew();
        if (null === $this->collM2Ps || null !== $criteria  || $partial) {
            if ($this->isNew() && null === $this->collM2Ps) {
                // return empty collection
                $this->initM2Ps();
            } else {
                $collM2Ps = ChildM2PQuery::create(null, $criteria)
                    ->filterByPage($this)
                    ->find($con);

                if (null !== $criteria) {
                    if (false !== $this->collM2PsPartial && count($collM2Ps)) {
                        $this->initM2Ps(false);

                        foreach ($collM2Ps as $obj) {
                            if (false == $this->collM2Ps->contains($obj)) {
                                $this->collM2Ps->append($obj);
                            }
                        }

                        $this->collM2PsPartial = true;
                    }

                    return $collM2Ps;
                }

                if ($partial && $this->collM2Ps) {
                    foreach ($this->collM2Ps as $obj) {
                        if ($obj->isNew()) {
                            $collM2Ps[] = $obj;
                        }
                    }
                }

                $this->collM2Ps = $collM2Ps;
                $this->collM2PsPartial = false;
            }
        }

        return $this->collM2Ps;
    }