code: def actions(self, state):
          'actions are index where we can make a move'
          actions = []
          for index, char in enumerate(state):
              if char == '_':
                  actions.append(index)
          return actionf actions(self, state):
          'actions are index where we can make a move'
          actions = []
          for index, char in enumerate(state):
              if char == '_':
                  actions.append(index)
          return actions
docs: actions are index where we can make a move