text: #Keep all the biolink classes as constants to keep from having to handle name changes.
  # of course bigger changes will require code changes as well.
  
  ANATOMICAL_ENTITY = 'biolink:AnatomicalEntity'
  GROSS_ANATOMICAL_STRUCTURE = 'biolink:GrossAnatomicalStructure'
  CELL = 'biolink:Cell'
  CELLULAR_COMPONENT = 'biolink:CellularComponent'
  GENE = 'biolink:Gene'
  PROTEIN = 'biolink:Protein'
  GENEORPROTEIN = 'biolink:GeneOrGeneProduct'
  DISEASE = 'biolink:Disease'
  PHENOTYPIC_FEATURE = 'biolink:PhenotypicFeature'
  BIOLOGICAL_PROCESS = 'biolink:BiologicalProcess'
  MOLECULAR_ACTIVITY = 'biolink:MolecularActivity'
  PATHWAY = 'biolink:Pathway'
  SMALL_MOLECULE='biolink:SmallMolecule'
  MOLECULAR_MIXTURE='biolink:MolecularMixture'
  CHEMICAL_ENTITY='biolink:ChemicalEntity'
  ORGANISM_TAXON='biolink:OrganismTaxon'
  POLYPEPTIDE='biolink:Polypeptide'
  GENE_FAMILY='biolink:GeneFamily'
  COMPLEX_CHEMICAL_MIXTURE='biolink:ComplexMolecularMixture'
  CHEMICAL_MIXTURE='biolink:ChemicalMixture'
  