Examples:
Obtaining an RDFXML format class
RDF::Format.for(:rdf) RDF::Format.for(:rdfxml) RDF::Format.for("etc/foaf.xml")
RDF::Format.for(:file_name => "etc/foaf.xml")
RDF::Format.for(:file_extension => "xml")
RDF::Format.for(:file_extension => "rdf")
RDF::Format.for(:content_type => "application/xml")
RDF::Format.for(:content_type => "application/rdf+xml")
Obtaining serialization format MIME types
RDF::Format.content_types
Obtaining serialization format file extension mappings
RDF::Format.file_extensions