- rdf_exporter.py: add isinstance(format, str) guard before .lower() so
non-string inputs (None, int, etc.) raise ValidationError consistently
instead of AttributeError; normalize via strip().lower() in one step
- 15_Export.ipynb: fix notebook cell using result['valid'] → result['overall_valid']
(validate_rdf() returns overall_valid, not valid); add trailing EOF newline
- test_rdf_exporter.py: add tests for non-string format → ValidationError
and for overall_valid key presence in validate_rdf() return value
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Add _format_aliases map in RDFExporter to accept 'ttl', 'nt', 'xml', 'rdf', 'json-ld' as shorthands for canonical format names
- Resolve alias at the start of export_to_rdf() before validation, leaving all existing callers unaffected
- Add TTL alias demo cell to cookbook/introduction/15_Export.ipynb
- Add tests/export/test_rdf_exporter.py covering alias parity, canonical formats, unsupported format error, and file export with format="ttl"
Closes#355
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>