code: def addGene(
              self, gene_id, gene_label, gene_type=None, gene_description=None
      ):
          ''' genes are classes '''
          if gene_type is None:
              gene_type = self.globaltt['gene']
          self.model.addClassToGraph(gene_id, gene_label, gene_type, gene_description)
  
          returf addGene(
              self, gene_id, gene_label, gene_type=None, gene_description=None
      ):
          ''' genes are classes '''
          if gene_type is None:
              gene_type = self.globaltt['gene']
          self.model.addClassToGraph(gene_id, gene_label, gene_type, gene_description)
  
          return
docs: genes are classes