docs: def find_by_index(self, cls, index_name, value):
          """Find all rows matching index query - as per the gludb spec."""
          cur = self._conn().cursor()
  
          query = 'select id,value from %s where %s = ?' % (
              cls.get_table_name(),
              index_name
          )
  
          found = []
          for row in cur.execute(query, (value,)):
              id, data = row[0], row[1]
              obj = cls.from_data(data)
              assert id == obj.id
              found.append(obj)
  
          cur.close()
  
          return found