code: def size(self):
          '''Return the number of links in the model'''
          count = 0
          cursor = self._db_coll.find()
          for item in cursor:
              if item['origin'] == '@_abbreviations':
                  continue
              count += len(item['rels'])
          return counf size(self):
          '''Return the number of links in the model'''
          count = 0
          cursor = self._db_coll.find()
          for item in cursor:
              if item['origin'] == '@_abbreviations':
                  continue
              count += len(item['rels'])
          return count
docs: Return the number of links in the model