setMinNumberOfElements example

        } else {
            $node = new PrototypedArrayNode($this->name, $this->parent, $this->pathSeparator);

            $this->validatePrototypeNode($node);

            if (null !== $this->key) {
                $node->setKeyAttribute($this->key, $this->removeKeyItem);
            }

            if (true === $this->atLeastOne || false === $this->allowEmptyValue) {
                $node->setMinNumberOfElements(1);
            }

            if ($this->default) {
                if (!\is_array($this->defaultValue)) {
                    throw new \InvalidArgumentException(sprintf('%s: the default value of an array node has to be an array.', $node->getPath()));
                }

                $node->setDefaultValue($this->defaultValue);
            }

            if (false !== $this->addDefaultChildren) {