According to the strictyaml author (https://github.com/crdoconnor/strictyaml/blob/master/FAQ.rst#why-is-strictyaml-built-upon-ruamelyaml): “ruamel.yaml is probably the best spec-adhering YAML parser for python.

Unlike pyyaml it does not require the C yaml library to be installed, and it is capable of loading, editing and saving YAML while preserving comments, which pyyaml does not.”