Where are the examples (or docs for that matter) about filters???

Where is the detailed documentation with examples, of how to build reports with complex (or even trivial) filters with the PHP library??

Here:
https://developers.google.com/analytics/devguides/reporting/data/v1/basics#dimension_filters
Some (too basic) example of filters in raw HTTP but no mention of PHP.

Here:
http://googleapis.github.io/google-cloud-php/#/docs/analytics-data/v0.8.0/analyticsdata/v1beta/readme
The only one example in PHP is one request, not only with no filters but with no parameters whatsoever.

Here:
https://developers.google.com/analytics/devguides/reporting/data/v1/rest/v1beta/FilterExpression#StringFilter
Some more details about filters but no clue as to how to translate it into PHP code.

This is pathetic.