code: def iter_feasible_configurations(cur):
      
      select = \
          """
          SELECT num_variables, feasible_configurations, energies
          FROM feasible_configurations
          """
      for num_variables, feasible_configurations, energies in cur.execute(select):
          configs = json.loads(feasible_configurations)
          energies = json.loads(energies)
  
          yield {_decode_config(config, num_variables): energy
                 for config, energy in zip(configs, energies)}
docs: Iterate over all of the sets of feasible configurations in the cache.
  
      Args:
          cur (:class:`sqlite3.Cursor`): An sqlite3 cursor. This function
              is meant to be run within a :obj:`with` statement.
  
      Yields:
          dict[tuple(int): number]: The feasible_configurations.