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- (Fixed) YAML values like "1", "1.0", "yes", "True" are converted to strings, not to int, float and bool respectively.
- (Changed) ``ruamel.yaml`` replaces ``pyyaml`` as supported YAML parser.
- (Changed) Use ``schema`` instead of ``pykwalify`` (which unfortunately freezes its dependencies versions)
to validate (the structure of) YAML files.
- (Changed) ``import_from_yaml`` raises ``StatechartError`` instead of ``SchemaError`` if it cannot validate given
YAML against the predefined schema.