code: def count_relations(self) -> int:
          
          if self.edge_model is ...:
              raise Bio2BELMissingEdgeModelError('edge_edge model is undefined/count_bel_relations is not overridden')
          elif isinstance(self.edge_model, list):
              return sum(self._count_model(m) for m in self.edge_model)
          else:
              return self._count_model(self.edge_model)
docs: Count the number of BEL relations generated.