code: def _add_disease_association_attributes(self, att_ind_start, att_mappings):
          
          disease_mappings = self.get_disease_mappings(att_ind_start)
          for vertex in self.graph.vs:
              assoc_diseases = vertex["associated_diseases"]
              if assoc_diseases is not None:
                  assoc_disease_ids = [disease_mappings[disease] for disease in assoc_diseases]
                  att_mappings[vertex.index].extend(assoc_disease_ids)
docs: Add disease association information to the attribute mapping dictionary.
  
          :param int att_ind_start: Start index for enumerating the attributes.
          :param dict att_mappings: Dictionary of mappings between vertices and enumerated attributes.