Customer/Entity/Customer.php
protected function findOneAddressBy($expression)
    {
        if (0 < $this->addresses->count()) {
            $criteria = Criteria::create()
                ->where($expression)
                ->setMaxResults(1);

            $matches = $this->addresses->matching($criteria);
            if ($matches->count() == 1) {
                return $matches->first();
            }
        }

        return null;
    }
protected function findOneAddressBy($expression)
    {
        if (0 < $this->addresses->count()) {
            $criteria = Criteria::create()
                ->where($expression)
                ->setMaxResults(1);

            $matches = $this->addresses->matching($criteria);
            if ($matches->count() == 1) {
                return $matches->first();
            }
        }

        return null;
    }
Finds one address by expression.

@param mixed $expression

@return Model\CustomerAddressInterface|null