code: def select_action(self, t, greedy_action_func, action_value=None):
      """Select an action.
  
      Args:
        t: current time step
        greedy_action_func: function with no argument that returns an action
        action_value (ActionValue): ActionValue object
      """
      raise NotImplementedError()
  
imports: from abc import ABCMeta
  from abc import abstractmethod
label_desc: Use image node_id 1 for calling the Explorer obj's underlying member method code with example usage: obj.select_action(t, greedy_action_func, action_value) without return types