assertion  retraction  graph  subject          predicate        object           datatype    annotation
1          0           graph  obo:CHEBI_33521  rdfs:label       metal atom       xsd:string  
1          0           graph  obo:CHEBI_33521  oio:id           CHEBI:33521      xsd:string  
1          0           graph  obo:CHEBI_33521  rdfs:subClassOf  obo:CHEBI_33250  _IRI        
1          0           graph  obo:CHEBI_33521  rdf:type         owl:Class        _IRI