assertion  retraction  graph  subject          predicate        object           datatype  annotation
1          0           graph  obo:CHEBI_50893  rdfs:subClassOf  obo:CHEBI_33833  _IRI      
1          0           graph  obo:CHEBI_35875  rdfs:subClassOf  obo:CHEBI_33833  _IRI      
1          0           graph  obo:CHEBI_38179  rdfs:subClassOf  obo:CHEBI_33833  _IRI