Scrutinizer Auto-Fixes

@schmittjoh requested this pull request.

This patch was automatically generated as part of the following inspection:
https://scrutinizer-ci.com/g/schmittjoh/serializer/inspections/018381c5-d5ff-41b5-8776-cc9ea77811ca

Enabled analysis tools:
 - PHP Analyzer
 - PHP Mess Detector
 - PHP Copy/Paste Detector
 - PHP PDepend